This specification is available in the following formats: single page HTML, multipage HTML, full specification. This is revision 1.4938.
Copyright © 2011 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
The bulk of the text of this specification is also available in the WHATWG Web Applications 1.0 specification, under a license that permits reuse of the specification text.
This document is a strict subset of the full HTML5 specification that omits user-agent (UA) implementation details. It is targeted toward Web authors and others who are not UA implementors and who want a view of the HTML specification that focuses more precisely on details relevant to using the HTML language to create Web documents and Web applications. Because this document does not provide implementation conformance criteria, UA implementors should not rely on it, but should instead refer to the full HTML5 specification.
This document is an automated redaction of the full HTML5 specification. As such, the two documents are supposed to agree on normative matters concerning Web authors. However, if the documents disagree, this is a bug in the redaction process and the unredacted full HTML specification takes precedence. Readers are encouraged to report such discrepancies as bugs in the bug tracking system of the HTML Working Group.
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
If you wish to make comments regarding this document in a manner that is tracked by the W3C, please submit them via using our public bug database. If you do not have an account then you can enter feedback using this form:
If you cannot do this then you can also e-mail feedback to public-html-comments@w3.org (subscribe, archives), and arrangements will be made to transpose the comments to our public bug database. Alternatively, you can e-mail feedback to whatwg@whatwg.org (subscribe, archives). The editor guarantees that all substantive feedback sent to this list will receive a reply. However, such feedback is not considered formal feedback for the W3C process. All feedback is welcome.
The working groups maintains a list of all bug reports that the editor has not yet tried to address and a list of issues for which the chairs have not yet declared a decision. The editor also maintains a list of all e-mails that he has not yet tried to address. These bugs, issues, and e-mails apply to multiple HTML-related specifications, not just this one.
Implementors should be aware that this specification is not stable. Implementors who are not taking part in the discussions are likely to find the specification changing out from under them in incompatible ways. Vendors interested in implementing this specification before it eventually reaches the Candidate Recommendation stage should join the aforementioned mailing lists and take part in the discussions.
The publication of this document by the W3C as a W3C First Public Working Draft does not imply that all of the participants in the W3C HTML working group endorse the contents of the specification. Indeed, for any section of the specification, one can usually find many members of the working group or of the W3C as a whole who object strongly to the current text, the existence of the section at all, or the idea that the working group should even spend time discussing the concept of that section.
A number of formal objections are open against this document:
The HTML Working Group chairs maintain a complete list of all current formal objections; that list may change as this document progresses.
There are also a number of open issues related to this document, for which working-group decisions still need to be made:
The HTML Working Group chairs maintain a complete list of all currently open HTML Working Group issues; that list may change as this document progresses.
Activities are being pursued by some members of the HTML Working Group to provide new information related to this document, with the intent of reopening the following issues:
The HTML Working Group chairs maintain a complete list of all HTML Working Group issues for which new information is known to be being pursued; that list may change as this document progresses.
A list of other potential accessibility related issues is also available.
W3C anticipates that there will be changes to this specification as a result of the resolution of Last Call issues. Per the usual W3C Process, any significant changes to the specification will trigger a subsequent Last Call.
The latest stable version of the editor's draft of the full HTML5 specification is always available on the W3C CVS server and in the WHATWG Subversion repository. The latest editor's working copy (which may contain unfinished text in the process of being prepared) contains the latest draft text of this specification (amongst others). For more details, please see the WHATWG FAQ.
There are various ways to follow the change history for the HTML specifications:
svn checkout http://svn.whatwg.org/webapps/
The W3C HTML Working Group is the W3C working group responsible for this specification's progress along the W3C Recommendation track. This specification is the 07 July 2011 First Public Working Draft.
Work on this specification is also done at the WHATWG. The W3C HTML working group actively pursues convergence with the WHATWG, as required by the W3C HTML working group charter.
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
a
elementem
elementstrong
elementsmall
elements
elementcite
elementq
elementdfn
elementabbr
elementtime
elementcode
elementvar
elementsamp
elementkbd
elementsub
and sup
elementsi
elementb
elementu
elementmark
elementruby
elementrt
elementrp
elementbdi
elementbdo
elementspan
elementbr
elementwbr
elementimg
element
iframe
elementembed
elementobject
elementparam
elementvideo
elementaudio
elementsource
elementtrack
elementcanvas
elementmap
elementarea
elementform
elementfieldset
elementlegend
elementlabel
elementinput
element
type
attribute
input
element attributes
autocomplete
attributedirname
attributelist
attributereadonly
attributesize
attributerequired
attributemultiple
attributemaxlength
attributepattern
attributemin
and max
attributesstep
attributeplaceholder
attributeinput
element APIsbutton
elementselect
elementdatalist
elementoptgroup
elementoption
elementtextarea
elementkeygen
elementoutput
elementprogress
elementmeter
elementa
and area
elementsalternate
"author
"bookmark
"external
"help
"icon
"license
"nofollow
"noreferrer
"pingback
"prefetch
"search
"sidebar
"stylesheet
"tag
"The World Wide Web's markup language has always been HTML. HTML was primarily designed as a language for semantically describing scientific documents, although its general design and adaptations over the years have enabled it to be used to describe a number of other types of documents.
The main area that has not been adequately addressed by HTML is a vague subject referred to as Web Applications. This specification attempts to rectify this, while at the same time updating the HTML specifications to address issues raised in the past few years.
This specification is intended for authors of documents and scripts that use the features defined in this specification.
This document is probably not suited to readers who do not already have at least a passing familiarity with Web technologies, as in places it sacrifices clarity for precision, and brevity for completeness. More approachable tutorials and authoring guides can provide a gentler introduction to the topic.
In particular, familiarity with the basics of DOM Core and DOM Events is necessary for a complete understanding of some of the more technical parts of this specification. An understanding of Web IDL, HTTP, XML, Unicode, character encodings, JavaScript, and CSS will also be helpful in places but is not essential.
This specification is limited to providing a semantic-level markup language and associated semantic-level scripting APIs for authoring accessible pages on the Web ranging from static documents to dynamic applications.
The scope of this specification does not include providing mechanisms for media-specific customization of presentation (although default rendering rules for Web browsers are included at the end of this specification, and several mechanisms for hooking into CSS are provided as part of the language).
The scope of this specification is not to describe an entire operating system. In particular, hardware configuration software, image manipulation tools, and applications that users would be expected to use with high-end workstations on a daily basis are out of scope. In terms of applications, this specification is targeted specifically at applications that would be expected to be used by users on an occasional basis, or regularly but from disparate locations, with low CPU requirements. For instance online purchasing systems, searching systems, games (especially multiplayer online games), public telephone books or address books, communications software (e-mail clients, instant messaging clients, discussion software), document editing software, etc.
For its first five years (1990-1995), HTML went through a number of revisions and experienced a number of extensions, primarily hosted first at CERN, and then at the IETF.
With the creation of the W3C, HTML's development changed venue again. A first abortive attempt at extending HTML in 1995 known as HTML 3.0 then made way to a more pragmatic approach known as HTML 3.2, which was completed in 1997. HTML4 followed, reaching completion in 1998.
At this time, the W3C membership decided to stop evolving HTML and instead begin work on an XML-based equivalent, called XHTML. This effort started with a reformulation of HTML4 in XML, known as XHTML 1.0, which added no new features except the new serialization, and which was completed in 2000. After XHTML 1.0, the W3C's focus turned to making it easier for other working groups to extend XHTML, under the banner of XHTML Modularization. In parallel with this, the W3C also worked on a new language that was not compatible with the earlier HTML and XHTML languages, calling it XHTML2.
Around the time that HTML's evolution was stopped in 1998, parts of the API for HTML developed by browser vendors were specified and published under the name DOM Level 1 (in 1998) and DOM Level 2 Core and DOM Level 2 HTML (starting in 2000 and culminating in 2003). These efforts then petered out, with some DOM Level 3 specifications published in 2004 but the working group being closed before all the Level 3 drafts were completed.
In 2003, the publication of XForms, a technology which was positioned as the next generation of Web forms, sparked a renewed interest in evolving HTML itself, rather than finding replacements for it. This interest was borne from the realization that XML's deployment as a Web technology was limited to entirely new technologies (like RSS and later Atom), rather than as a replacement for existing deployed technologies (like HTML).
A proof of concept to show that it was possible to extend HTML4's forms to provide many of the features that XForms 1.0 introduced, without requiring browsers to implement rendering engines that were incompatible with existing HTML Web pages, was the first result of this renewed interest. At this early stage, while the draft was already publicly available, and input was already being solicited from all sources, the specification was only under Opera Software's copyright.
The idea that HTML's evolution should be reopened was tested at a W3C workshop in 2004, where some of the principles that underlie the HTML5 work (described below), as well as the aforementioned early draft proposal covering just forms-related features, were presented to the W3C jointly by Mozilla and Opera. The proposal was rejected on the grounds that the proposal conflicted with the previously chosen direction for the Web's evolution; the W3C staff and membership voted to continue developing XML-based replacements instead.
Shortly thereafter, Apple, Mozilla, and Opera jointly announced their intent to continue working on the effort under the umbrella of a new venue called the WHATWG. A public mailing list was created, and the draft was moved to the WHATWG site. The copyright was subsequently amended to be jointly owned by all three vendors, and to allow reuse of the specification.
The WHATWG was based on several core principles, in particular that technologies need to be backwards compatible, that specifications and implementations need to match even if this means changing the specification rather than the implementations, and that specifications need to be detailed enough that implementations can achieve complete interoperability without reverse-engineering each other.
The latter requirement in particular required that the scope of the HTML5 specification include what had previously been specified in three separate documents: HTML4, XHTML1, and DOM2 HTML. It also meant including significantly more detail than had previously been considered the norm.
In 2006, the W3C indicated an interest to participate in the development of HTML5 after all, and in 2007 formed a working group chartered to work with the WHATWG on the development of the HTML5 specification. Apple, Mozilla, and Opera allowed the W3C to publish the specification under the W3C copyright, while keeping a version with the less restrictive license on the WHATWG site.
Since then, both groups have been working together.
The HTML specification published by the WHATWG is not identical to this specification. At the time of this publication, the main differences were that the WHATWG version included features not included in this W3C version: some features have been omitted, but may be considered for future revisions of HTML beyond HTML5; and other features were omitted because at the W3C they are published as separate specifications.
A separate document has been published by the W3C HTML working group to document the differences between this specification and the language described in the HTML4 specification. [HTMLDIFF]
It must be admitted that many aspects of HTML appear at first glance to be nonsensical and inconsistent.
HTML, its supporting DOM APIs, as well as many of its supporting technologies, have been developed over a period of several decades by a wide array of people with different priorities who, in many cases, did not know of each other's existence.
Features have thus arisen from many sources, and have not always been designed in especially consistent ways. Furthermore, because of the unique characteristics of the Web, implementation bugs have often become de-facto, and now de-jure, standards, as content is often unintentionally written in ways that rely on them before they can be fixed.
Despite all this, efforts have been made to adhere to certain design goals. These are described in the next few subsections.
To avoid exposing Web authors to the complexities of multithreading, the HTML and DOM APIs are designed such that no script can ever detect the simultaneous execution of other scripts. Even with workers, the intent is that the behavior of implementations can be thought of as completely serializing the execution of all scripts in all browsing contexts.
The navigator.yieldForStorageUpdates()
method, in this model, is equivalent to allowing other scripts to run while the calling script is blocked.
This specification interacts with and relies on a wide variety of other specifications. In certain circumstances, unfortunately, conflicting needs have led to this specification violating the requirements of these other specifications. Whenever this has occurred, the transgressions have each been noted as a "willful violation", and the reason for the violation has been noted.
This specification defines an abstract language for describing documents and applications, and some APIs for interacting with in-memory representations of resources that use this language.
The in-memory representation is known as "DOM HTML", or "the DOM" for short. This specification defines version 5 of DOM HTML, known as "DOM5 HTML".
There are various concrete syntaxes that can be used to transmit resources that use this abstract language, two of which are defined in this specification.
The first such concrete syntax is the HTML syntax. This is the format suggested for most authors. It is compatible with most legacy Web browsers. If a document is transmitted with an HTML MIME type, such as text/html
, then it will be processed as an HTML document by Web browsers. This specification defines version 5 of the HTML syntax, known as "HTML5".
The second concrete syntax is the XHTML syntax, which is an application of XML. When a document is transmitted with an XML MIME type, such as application/xhtml+xml
, then it is treated as an XML document by Web browsers, to be parsed by an XML processor. Authors are reminded that the processing for XML and HTML differs; in particular, even minor syntax errors will prevent a document labeled as XML from being rendered fully, whereas they would be ignored in the HTML syntax. This specification defines version 5 of the XHTML syntax, known as "XHTML5".
The DOM, the HTML syntax, and XML cannot all represent the same content. For example, namespaces cannot be represented using the HTML syntax, but they are supported in the DOM and in XML. Similarly, documents that use the noscript
feature can be represented using the HTML syntax, but cannot be represented with the DOM or in XML. Comments that contain the string "-->
" can only be represented in the DOM, not in the HTML and XML syntaxes.
This specification is divided into the following major sections:
There are also some appendices, defining rendering rules for Web browsers and listing obsolete features and IANA considerations.
This specification should be read like all other specifications. First, it should be read cover-to-cover, multiple times. Then, it should be read backwards at least once. Then it should be read by picking random sections from the contents list and following all the cross-references.
This is a definition, requirement, or explanation.
This is a note.
This is an example.
This is an open issue.
This is a warning.
interface Example { // this is an IDL definition };
method
( [ optionalArgument ] )This is a note to authors describing the usage of an interface.
/* this is a CSS fragment */
The defining instance of a term is marked up like this. Uses of that term are marked up like this or like this.
The defining instance of an element, attribute, or API is marked up like this
. References to that element, attribute, or API are marked up like this
.
Other code fragments are marked up like this
.
Variables are marked up like this.
A basic HTML document looks like this:
<!DOCTYPE html> <html> <head> <title>Sample page</title> </head> <body> <h1>Sample page</h1> <p>This is a <a href="demo.html">simple</a> sample.</p> <!-- this is a comment --> </body> </html>
HTML documents consist of a tree of elements and text. Each element is denoted in the source by a start tag, such as "<body>
", and an end tag, such as "</body>
". (Certain start tags and end tags can in certain cases be omitted and are implied by other tags.)
Tags have to be nested such that elements are all completely within each other, without overlapping:
<p>This is <em>very <strong>wrong</em>!</strong></p>
<p>This <em>is <strong>correct</strong>.</em></p>
This specification defines a set of elements that can be used in HTML, along with rules about the ways in which the elements can be nested.
Elements can have attributes, which control how the elements work. In the example below, there is a hyperlink, formed using the a
element and its href
attribute:
<a href="demo.html">simple</a>
Attributes are placed inside the start tag, and consist of a name and a value, separated by an "=
" character. The attribute value can remain unquoted if it doesn't contain spaces or any of "
'
`
=
<
or >
. Otherwise, it has to be quoted using either single or double quotes. The value, along with the "=
" character, can be omitted altogether if the value is the empty string.
<!-- empty attributes --> <input name=address disabled> <input name=address disabled=""> <!-- attributes with a value --> <input name=address maxlength=200> <input name=address maxlength='200'> <input name=address maxlength="200">
HTML user agents (e.g. Web browsers) then parse this markup, turning it into a DOM (Document Object Model) tree. A DOM tree is an in-memory representation of a document.
DOM trees contain several kinds of nodes, in particular a DOCTYPE node, elements, text nodes, and comment nodes.
The markup snippet at the top of this section would be turned into the following DOM tree:
html
html
The root element of this tree is the html
element, which is the element always found at the root of HTML documents. It contains two elements, head
and body
, as well as a text node between them.
There are many more text nodes in the DOM tree than one would initially expect, because the source contains a number of spaces (represented here by "␣") and line breaks ("⏎") that all end up as text nodes in the DOM. However, for historical reasons not all of the spaces and line breaks in the original markup appear in the DOM. In particular, all the whitespace before head
start tag ends up being dropped silently, and all the whitespace after the body
end tag ends up placed at the end of the body
.
The head
element contains a title
element, which itself contains a text node with the text "Sample page". Similarly, the body
element contains an h1
element, a p
element, and a comment.
This DOM tree can be manipulated from scripts in the page. Scripts (typically in JavaScript) are small programs that can be embedded using the script
element or using event handler content attributes. For example, here is a form with a script that sets the value of the form's output
element to say "Hello World":
<form name="main"> Result: <output name="result"></output> <script> document.forms.main.elements.result.value = 'Hello World'; </script> </form>
Each element in the DOM tree is represented by an object, and these objects have APIs so that they can be manipulated. For instance, a link (e.g. the a
element in the tree above) can have its "href
" attribute changed in several ways:
var a = document.links[0]; // obtain the first link in the document a.href = 'sample.html'; // change the destination URL of the link a.protocol = 'https'; // change just the scheme part of the URL a.setAttribute('href', 'http://example.com/'); // change the content attribute directly
Since DOM trees are used as the way to represent HTML documents when they are processed and presented by implementations (especially interactive implementations like Web browsers), this specification is mostly phrased in terms of DOM trees, instead of the markup described above.
HTML documents represent a media-independent description of interactive content. HTML documents might be rendered to a screen, or through a speech synthesizer, or on a braille display. To influence exactly how such rendering takes place, authors can use a styling language such as CSS.
In the following example, the page has been made yellow-on-blue using CSS.
<!DOCTYPE html> <html> <head> <title>Sample styled page</title> <style> body { background: navy; color: yellow; } </style> </head> <body> <h1>Sample styled page</h1> <p>This page is just a demo.</p> </body> </html>
For more details on how to use HTML, authors are encouraged to consult tutorials and guides. Some of the examples included in this specification might also be of use, but the novice author is cautioned that this specification, by necessity, defines the language with a level of detail that might be difficult to understand at first.
Unlike previous versions of the HTML specification, this specification defines in some detail the required processing for invalid documents as well as valid documents.
However, even though the processing of invalid content is in most cases well-defined, conformance requirements for documents are still important: in practice, interoperability (the situation in which all implementations process particular content in a reliable and identical or equivalent way) is not the only goal of document conformance requirements. This section details some of the more common reasons for still distinguishing between a conforming document and one with errors.
The majority of presentational features from previous versions of HTML are no longer allowed. Presentational markup in general has been found to have a number of problems:
While it is possible to use presentational markup in a way that provides users of assistive technologies (ATs) with an acceptable experience (e.g. using ARIA), doing so is significantly more difficult than doing so when using semantically-appropriate markup. Furthermore, even using such techniques doesn't help make pages accessible for non-AT non-graphical users, such as users of text-mode browsers.
Using media-independent markup, on the other hand, provides an easy way for documents to be authored in such a way that they work for more users (e.g. text browsers).
It is significantly easier to maintain a site written in such a way that the markup is style-independent. For example, changing the color of a site that uses <font color="">
throughout requires changes across the entire site, whereas a similar change to a site based on CSS can be done by changing a single file.
Presentational markup tends to be much more redundant, and thus results in larger document sizes.
For those reasons, presentational markup has been removed from HTML in this version. This change should not come as a surprise; HTML4 deprecated presentational markup many years ago and provided a mode (HTML4 Transitional) to help authors move away from presentational markup; later, XHTML 1.1 went further and obsoleted those features altogether.
The only remaining presentational markup features in HTML are the style
attribute and the style
element. Use of the style
attribute is somewhat discouraged in production environments, but it can be useful for rapid prototyping (where its rules can be directly moved into a separate style sheet later) and for providing specific styles in unusual cases where a separate style sheet would be inconvenient. Similarly, the style
element can be useful in syndication or for page-specific styles, but in general an external style sheet is likely to be more convenient when the styles apply to multiple pages.
It is also worth noting that some elements that were previously presentational have been redefined in this specification to be media-independent: b
, i
, hr
, s
, small
, and u
.
The syntax of HTML is constrained to avoid a wide variety of problems.
Certain invalid syntax constructs, when parsed, result in DOM trees that are highly unintuitive.
To allow user agents to be used in controlled environments without having to implement the more bizarre and convoluted error handling rules, user agents are permitted to fail whenever encountering a parse error.
Some error-handling behavior, such as the behavior for the <table><hr>...
example mentioned above, are incompatible with streaming user agents (user agents that process HTML files in one pass, without storing state). To avoid interoperability problems with such user agents, any syntax resulting in such behavior is considered invalid.
When a user agent based on XML is connected to an HTML parser, it is possible that certain invariants that XML enforces, such as comments never containing two consecutive hyphens, will be violated by an HTML file. Handling this can require that the parser coerce the HTML DOM into an XML-compatible infoset. Most syntax constructs that require such handling are considered invalid.
Certain syntax constructs can result in disproportionally poor performance. To discourage the use of such constructs, they are typically made non-conforming.
For example, the following markup results in poor performance, since all the unclosed i
elements have to be reconstructed in each paragraph, resulting in progressively more elements in each paragraph:
<p><i>He dreamt. <p><i>He dreamt that he ate breakfast. <p><i>Then lunch. <p><i>And finally dinner.
The resulting DOM for this fragment would be:
There are syntax constructs that, for historical reasons, are relatively fragile. To help reduce the number of users who accidentally run into such problems, they are made non-conforming.
For example, the parsing of certain named character references in attributes happens even with the closing semicolon being omitted. It is safe to include an ampersand followed by letters that do not form a named character reference, but if the letters are changed to a string that does form a named character reference, they will be interpreted as that character instead.
In this fragment, the attribute's value is "?bill&ted
":
<a href="?bill&ted">Bill and Ted</a>
In the following fragment, however, the attribute's value is actually "?art©
", not the intended "?art©
", because even without the final semicolon, "©
" is handled the same as "©
" and thus gets interpreted as "©
":
<a href="?art©">Art and Copy</a>
To avoid this problem, all named character references are required to end with a semicolon, and uses of named character references without a semicolon are flagged as errors.
Thus, the correct way to express the above cases is as follows:
<a href="?bill&ted">Bill and Ted</a> <!-- &ted is ok, since it's not a named character reference -->
<a href="?art&copy">Art and Copy</a> <!-- the & has to be escaped, since © is a named character reference -->
Certain syntax constructs are known to cause especially subtle or serious problems in legacy user agents, and are therefore marked as non-conforming to help authors avoid them.
For example, this is why the U+0060 GRAVE ACCENT character (`) is not allowed in unquoted attributes. In certain legacy user agents, it is sometimes treated as a quote character.
Another example of this is the DOCTYPE, which is required to trigger no-quirks mode, because the behavior of legacy user agents in quirks mode is often largely undocumented.
Certain restrictions exist purely to avoid known security problems.
For example, the restriction on using UTF-7 exists purely to avoid authors falling prey to a known cross-site-scripting attack using UTF-7.
Markup where the author's intent is very unclear is often made non-conforming. Correcting these errors early makes later maintenance easier.
When a user makes a simple typo, it is helpful if the error can be caught early, as this can save the author a lot of debugging time. This specification therefore usually considers it an error to use element names, attribute names, and so forth, that do not match the names defined in this specification.
For example, if the author typed <capton>
instead of <caption>
, this would be flagged as an error and the author could correct the typo immediately.
In order to allow the language syntax to be extended in the future, certain otherwise harmless features are disallowed.
For example, "attributes" in end tags are ignored currently, but they are invalid, in case a future change to the language makes use of that syntax feature without conflicting with already-deployed (and valid!) content.
Some authors find it helpful to be in the practice of always quoting all attributes and always including all optional tags, preferring the consistency derived from such custom over the minor benefits of terseness afforded by making use of the flexibility of the HTML syntax. To aid such authors, conformance checkers can provide modes of operation wherein such conventions are enforced.
Beyond the syntax of the language, this specification also places restrictions on how elements and attributes can be specified. These restrictions are present for similar reasons:
To avoid misuse of elements with defined meanings, content models are defined that restrict how elements can be nested when such nestings would be of dubious value.
For example, this specification disallows nesting a section
element inside a kbd
element, since it is highly unlikely for an author to indicate that an entire section should be keyed in.
Similarly, to draw the author's attention to mistakes in the use of elements, clear contradictions in the semantics expressed are also considered conformance errors.
In the fragments below, for example, the semantics are nonsensical: a separator cannot simultaneously be a cell, nor can a radio button be a progress bar.
<hr role="cell">
<input type=radio role=progressbar>
Another example is the restrictions on the content models of the ul
element, which only allows li
element children. Lists by definition consist just of zero or more list items, so if a ul
element contains something other than an li
element, it's not clear what was meant.
Certain elements have default styles or behaviors that make certain combinations likely to lead to confusion. Where these have equivalent alternatives without this problem, the confusing combinations are disallowed.
For example, div
elements are rendered as block boxes, and span
elements as inline boxes. Putting a block box in an inline box is unnecessarily confusing; since either nesting just div
elements, or nesting just span
elements, or nesting span
elements inside div
elements all serve the same purpose as nesting a div
element in a span
element, but only the latter involves a block box in an inline box, the latter combination is disallowed.
Another example would be the way interactive content cannot be nested. For example, a button
element cannot contain a textarea
element. This is because the default behavior of such nesting interactive elements would be highly confusing to users. Instead of nesting these elements, they can be placed side by side.
Sometimes, something is disallowed because allowing it would likely cause author confusion.
For example, setting the disabled
attribute to the value "false
" is disallowed, because despite the appearance of meaning that the element is enabled, it in fact means that the element is disabled (what matters for implementations is the presence of the attribute, not its value).
Some conformance errors simplify the language that authors need to learn.
For example, the area
element's shape
attribute, despite accepting both circ
and circle
values in practice as synonyms, disallows the use of the circ
value, so as to simplify tutorials and other learning aids. There would be no benefit to
allowing both, but it would cause extra confusion when teaching the language.
Certain elements are parsed in somewhat eccentric ways (typically for historical reasons), and their content model restrictions are intended to avoid exposing the author to these issues.
For example, a form
element isn't allowed inside phrasing content, because when parsed as HTML, a form
element's start tag will imply a p
element's end tag. Thus, the following markup results in two paragraphs, not one:
<p>Welcome. <form><label>Name:</label> <input></form>
It is parsed exactly like the following:
<p>Welcome. </p><form><label>Name:</label> <input></form>
Some errors are intended to help prevent script problems that would be hard to debug.
This is why, for instance, it is non-conforming to have two id
attributes with the same value. Duplicate IDs lead to the wrong element being selected, with sometimes disastrous effects whose cause is hard to determine.
Some constructs are disallowed because historically they have been the cause of a lot of wasted authoring time, and by encouraging authors to avoid making them, authors can save time in future efforts.
For example, a script
element's src
attribute causes the element's contents to be ignored. However, this isn't obvious, especially if the element's contents appear to be executable script — which can lead to authors spending a lot of time trying to debug the inline script without realizing that it is not executing. To reduce this problem, this specification makes it non-conforming to have executable script in a script
element when the src
attribute is present. This means that authors who are validating their documents are less likely to waste time with this kind of mistake.
Some authors like to write files that can be interpreted as both XML and HTML with similar results. Though this practice is discouraged in general due to the myriad of subtle complications involved (especially when involving scripting, styling, or any kind of automated serialization), this specification has a few restrictions intended to at least somewhat mitigate the difficulties. This makes it easier for authors to use this as a transitionary step when migrating between HTML and XHTML.
For example, there are somewhat complicated rules surrounding the lang
and xml:lang
attributes intended to keep the two synchronized.
Another example would be the restrictions on the values of xmlns
attributes in the HTML serialization, which are intended to ensure that elements in conforming documents end up in the same namespaces whether processed as HTML or XML.
As with the restrictions on the syntax intended to allow for new syntax in future revisions of the language, some restrictions on the content models of elements and values of attributes are intended to allow for future expansion of the HTML vocabulary.
For example, limiting the values of the target
attribute that start with an U+005F LOW LINE character (_) to only specific predefined values allows new predefined values to be introduced at a future time without conflicting with author-defined values.
Certain restrictions are intended to support the restrictions made by other specifications.
For example, requiring that attributes that take media queries use only valid media queries reinforces the importance of following the conformance rules of that specification.
The following documents might be of interest to readers of this specification.
This Architectural Specification provides authors of specifications, software developers, and content developers with a common reference for interoperable text manipulation on the World Wide Web, building on the Universal Character Set, defined jointly by the Unicode Standard and ISO/IEC 10646. Topics addressed include use of the terms 'character', 'encoding' and 'string', a reference processing model, choice and identification of character encodings, character escaping, and string indexing.
Because Unicode contains such a large number of characters and incorporates the varied writing systems of the world, incorrect usage can expose programs or systems to possible security attacks. This is especially important as more and more products are internationalized. This document describes some of the security considerations that programmers, system analysts, standards developers, and users should take into account, and provides specific recommendations to reduce the risk of problems.
Web Content Accessibility Guidelines (WCAG) 2.0 covers a wide range of recommendations for making Web content more accessible. Following these guidelines will make content accessible to a wider range of people with disabilities, including blindness and low vision, deafness and hearing loss, learning disabilities, cognitive limitations, limited movement, speech disabilities, photosensitivity and combinations of these. Following these guidelines will also often make your Web content more usable to users in general.
A document that uses polyglot markup is a document that is a stream of bytes that parses into identical document trees (with the exception of the xmlns attribute on the root element) when processed as HTML and when processed as XML. Polyglot markup that meets a well defined set of constraints is interpreted as compatible, regardless of whether they are processed as HTML or as XHTML, per the HTML5 specification. Polyglot markup uses a specific DOCTYPE, namespace declarations, and a specific case — normally lower case but occasionally camel case — for element and attribute names. Polyglot markup uses lower case for certain attribute values. Further constraints include those on empty elements, named entity references, and the use of scripts and style.
This is draft documentation mapping HTML elements and attributes to accessibility API Roles, States and Properties on a variety of platforms. It provides recommendations on deriving the accessible names and descriptions for HTML elements. It also provides accessible feature implementation examples.
This specification refers to both HTML and XML attributes and IDL attributes, often in the same context. When it is not clear which is being referred to, they are referred to as content attributes for HTML and XML attributes, and IDL attributes for those defined on IDL interfaces. Similarly, the term "properties" is used for both JavaScript object properties and CSS properties. When these are ambiguous they are qualified as object properties and CSS properties respectively.
Generally, when the specification states that a feature applies to the HTML syntax or the XHTML syntax, it also includes the other. When a feature specifically only applies to one of the two languages, it is called out by explicitly stating that it does not apply to the other format, as in "for HTML, ... (this does not apply to XHTML)".
This specification uses the term document to refer to any use of HTML, ranging from short static documents to long essays or reports with rich multimedia, as well as to fully-fledged interactive applications.
For simplicity, terms such as shown, displayed, and visible might sometimes be used when referring to the way a document is rendered to the user. These terms are not meant to imply a visual medium; they must be considered to apply to other media in equivalent ways.
The term "transparent black" refers to the color with red, green, blue, and alpha channels all set to zero.
The specification uses the term supported when referring to whether a user agent has an implementation capable of decoding the semantics of an external resource. A format or type is said to be supported if the implementation can process an external resource of that format or type without critical aspects of the resource being ignored. Whether a specific resource is supported can depend on what features of the resource's format are in use.
For example, a PNG image would be considered to be in a supported format if its pixel data could be decoded and rendered, even if, unbeknownst to the implementation, the image also contained animation data.
A MPEG4 video file would not be considered to be in a supported format if the compression format used was not supported, even if the implementation could determine the dimensions of the movie from the file's metadata.
What some specifications, in particular the HTTP and URI specifications, refer to as a representation is referred to in this specification as a resource. [HTTP] [RFC3986]
The term MIME type is used to refer to what is sometimes called an Internet media type in protocol literature. The term media type in this specification is used to refer to the type of media intended for presentation, as used by the CSS specifications. [RFC2046] [MQ]
A string is a valid MIME type if it matches the media-type
rule defined in section 3.7 "Media Types" of RFC 2616. In particular, a valid MIME type may include MIME type parameters. [HTTP]
A string is a valid MIME type with no parameters if it matches the media-type
rule defined in section 3.7 "Media Types" of RFC 2616, but does not contain any U+003B SEMICOLON characters (;). In other words, if it consists only of a type and subtype, with no MIME Type parameters. [HTTP]
The term HTML MIME type is used to refer to the MIME types text/html
and text/html-sandboxed
.
A resource's critical subresources are those that the resource needs to have available to be correctly processed. Which resources are considered critical or not is defined by the specification that defines the resource's format. For CSS resources, only @import
rules introduce critical subresources; other resources, e.g. fonts or backgrounds, are not.
The term data:
URL refers to URLs that use the data:
scheme. [RFC2397]
To ease migration from HTML to XHTML, UAs conforming to this specification will place elements in HTML in the http://www.w3.org/1999/xhtml
namespace, at least for the purposes of the DOM and CSS. The term "HTML elements", when used in this specification, refers to any element in that namespace, and thus refers to both HTML and XHTML elements.
Except where otherwise stated, all elements defined or mentioned in this specification are in the http://www.w3.org/1999/xhtml
namespace, and all attributes defined or mentioned in this specification have no namespace.
Attribute names are said to be XML-compatible if they match the Name
production defined in XML, they contain no U+003A COLON characters (:), and their first three characters are not an ASCII case-insensitive match for the string "xml
". [XML]
The term XML MIME type is used to refer to the MIME types text/xml
, application/xml
, and any MIME type whose subtype ends with the four characters "+xml
". [RFC3023]
The root element of a Document
object is that Document
's first element child, if any. If it does not have one then the Document
has no root element.
The term root element, when not referring to a Document
object's root element, means the furthest ancestor element node of whatever node is being discussed, or the node itself if it has no ancestors. When the node is a part of the document, then the node's root element is indeed the document's root element; however, if the node is not currently part of the document tree, the root element will be an orphaned node.
When an element's root element is the root element of a Document
object, it is said to be in a Document
. An element is said to have been inserted into a document when its root element changes and is now the document's root element. Analogously, an element is said to have been removed from a document when its root element changes from being the document's root
element to being another element.
A node's home subtree is the subtree rooted at that node's root element. When a node is in a Document
, its home subtree is that Document
's tree.
The Document
of a Node
(such as an element) is the Document
that the Node
's ownerDocument
IDL attribute returns. When a Node
is in a Document
then that Document
is always the Node
's Document
, and the Node
's ownerDocument
IDL attribute thus always returns that
Document
.
The term tree order means a pre-order, depth-first traversal of DOM nodes involved (through the parentNode
/childNodes
relationship).
When it is stated that some element or attribute is ignored, or treated as some other value, or handled as if it was something else, this refers only to the processing of the node after it is in the DOM.
The term text node refers to any Text
node, including CDATASection
nodes; specifically, any Node
with node type TEXT_NODE
(3) or CDATA_SECTION_NODE
(4). [DOMCORE]
A content attribute is said to change value only if its new value is different than its previous value; setting an attribute to a value it already has does not change it.
The term empty, when used of an attribute value, text node, or string, means that the length of the text is zero (i.e. not even containing spaces or control characters).
Nodes can be cloned, as described in the DOM Core specification. For example, the cloneNode()
and importNode()
methods of the Node
interface both clone nodes, as do a number of algorithms in this specification. Certain HTML elements (in particular, input
and script
) apply additional requirements on how they are cloned. [DOMCORE]
The construction "a Foo
object", where Foo
is actually an interface, is sometimes used instead of the more accurate "an object implementing the interface Foo
".
An IDL attribute is said to be getting when its value is being retrieved (e.g. by author script), and is said to be setting when a new value is assigned to it.
If a DOM object is said to be live, then the attributes and methods on that object operate on the actual underlying data, not a snapshot of the data.
The terms fire and dispatch are used interchangeably in the context of events, as in the DOM Events specifications. The term trusted event is used as defined by the DOM Events specification. [DOMEVENTS]
The term plugin refers to a user-agent defined set of content handlers used by the user agent that can take part in the user agent's rendering of a Document
object, but that neither act as child browsing contexts of the Document
nor introduce any Node
objects to the Document
's DOM.
Typically such content handlers are provided by third parties, though a user agent can also designate built-in content handlers as plugins.
One example of a plugin would be a PDF viewer that is instantiated in a browsing context when the user navigates to a PDF file. This would count as a plugin regardless of whether the party that implemented the PDF viewer component was the same as that which implemented the user agent itself. However, a PDF viewer application that launches separate from the user agent (as opposed to using the same interface) is not a plugin by this definition.
This specification does not define a mechanism for interacting with plugins, as it is expected to be user-agent- and platform-specific. Some UAs might opt to support a plugin mechanism such as the Netscape Plugin API; others might use remote content converters or have built-in support for certain types. Indeed, this specification doesn't require user agents to support plugins at all. [NPAPI]
The preferred MIME name of a character encoding is the name or alias labeled as "preferred MIME name" in the IANA Character Sets registry, if there is one, or the encoding's name, if none of the aliases are so labeled. [IANACHARSET]
An ASCII-compatible character encoding is a single-byte or variable-length encoding in which the bytes 0x09, 0x0A, 0x0C, 0x0D, 0x20 - 0x22, 0x26, 0x27, 0x2C - 0x3F, 0x41 - 0x5A, and 0x61 - 0x7A, ignoring bytes that are the second and later bytes of multibyte sequences, all correspond to single-byte sequences that map to the same Unicode characters as those bytes in ANSI_X3.4-1968 (US-ASCII). [RFC1345]
This includes such encodings as Shift_JIS, HZ-GB-2312, and variants of ISO-2022, even though it is possible in these encodings for bytes like 0x70 to be part of longer sequences that are unrelated to their interpretation as ASCII. It excludes such encodings as UTF-7, UTF-16, GSM03.38, and EBCDIC variants.
The term Unicode character is used to mean a Unicode scalar value (i.e. any Unicode code point that is not a surrogate code point). [UNICODE]
All diagrams, examples, and notes in this specification are non-normative, as are all sections explicitly marked non-normative. Everything else in this specification is normative.
The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in the normative parts of this document are to be interpreted as described in RFC2119. For readability, these words do not appear in all uppercase letters in this specification. [RFC2119]
HTML has a wide number of extensibility mechanisms that can be used for adding semantics in a safe manner:
class
attribute to extend elements, effectively creating their own elements, while using the most applicable existing "real" HTML element, so that browsers and other tools that don't know of the extension can still support it somewhat well. This is the tack used by Microformats, for example.data-*=""
attributes. These are guaranteed to never be touched by browsers, and allow scripts to include data on HTML elements that scripts can then look for and process.<meta name="" content="">
mechanism to include page-wide metadata by registering extensions to the predefined set of metadata names.rel=""
mechanism to annotate links with specific meanings by registering extensions to the predefined set of link types. This is also used by Microformats.<script type="">
mechanism with a custom type, for further handling by inline or server-side scripts.embed
element. This is how Flash works.When adding new reflecting IDL attributes corresponding to content attributes of the form "x-vendor-feature
", the IDL attribute should be named "vendorFeature
" (i.e. the "x
" is dropped from the IDL attribute's name).
Comparing two strings in a case-sensitive manner means comparing them exactly, code point for code point.
Comparing two strings in an ASCII case-insensitive manner means comparing them exactly, code point for code point, except that the characters in the range U+0041 to U+005A (i.e. LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) and the corresponding characters in the range U+0061 to U+007A (i.e. LATIN SMALL LETTER A to LATIN SMALL LETTER Z) are considered to also match.
Comparing two strings in a compatibility caseless manner means using the Unicode compatibility caseless match operation to compare the two strings. [UNICODE]
Except where otherwise stated, string comparisons must be performed in a case-sensitive manner.
A string pattern is a prefix match for a string s when pattern is not longer than s and truncating s to pattern's length leaves the two strings as matches of each other.
There are various places in HTML that accept particular data types, such as dates or numbers. This section describes what the conformance criteria for content in those formats is, and how to parse them.
A number of attributes are boolean attributes. The presence of a boolean attribute on an element represents the true value, and the absence of the attribute represents the false value.
If the attribute is present, its value must either be the empty string or a value that is an ASCII case-insensitive match for the attribute's canonical name, with no leading or trailing whitespace.
The values "true" and "false" are not allowed on boolean attributes. To represent a false value, the attribute has to be omitted altogether.
Here is an example of a checkbox that is checked and disabled. The checked
and disabled
attributes are the boolean attributes.
<label><input type=checkbox checked name=cheese disabled> Cheese</label>
This could be equivalently written as this:
<label><input type=checkbox checked=checked name=cheese disabled=disabled> Cheese</label>
You can also mix styles; the following is still equivalent:
<label><input type='checkbox' checked name=cheese disabled=""> Cheese</label>
Some attributes are defined as taking one of a finite set of keywords. Such attributes are called enumerated attributes. The keywords are each defined to map to a particular state (several keywords might map to the same state, in which case some of the keywords are synonyms of each other; additionally, some of the keywords can be said to be non-conforming, and are only in the specification for historical reasons). In addition, two default states can be given. The first is the invalid value default, the second is the missing value default.
If an enumerated attribute is specified, the attribute's value must be an ASCII case-insensitive match for one of the given keywords that are not said to be non-conforming, with no leading or trailing whitespace.
When the attribute is specified, if its value is an ASCII case-insensitive match for one of the given keywords then that keyword's state is the state that the attribute represents. If the attribute value matches none of the given keywords, but the attribute has an invalid value default, then the attribute represents that state. Otherwise, if the attribute value matches none of the keywords but there is a missing value default state defined, then that is the state represented by the attribute. Otherwise, there is no default, and invalid values must be ignored.
When the attribute is not specified, if there is a missing value default state defined, then that is the state represented by the (missing) attribute. Otherwise, the absence of the attribute means that there is no state represented.
The empty string can be a valid keyword.
A string is a valid non-negative integer if it consists of one or more characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9).
A valid non-negative integer represents the number that is represented in base ten by that string of digits.
A string is a valid integer if it consists of one or more characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), optionally prefixed with a U+002D HYPHEN-MINUS character (-).
A valid integer without a U+002D HYPHEN-MINUS (-) prefix represents the number that is represented in base ten by that string of digits. A valid integer with a U+002D HYPHEN-MINUS (-) prefix represents the number represented in base ten by the string of digits that follows the U+002D HYPHEN-MINUS, subtracted from zero.
A string is a valid floating point number if it consists of:
A valid floating point number represents the number obtained by multiplying the significand by ten raised to the power of the exponent, where the significand is the first number, interpreted as base ten (including the decimal point and the number after the decimal point, if any, and interpreting the significand as a negative number if the whole string starts with a U+002D HYPHEN-MINUS character (-) and the number is not zero), and where the exponent is the number after the E, if any (interpreted as a negative number if there is a U+002D HYPHEN-MINUS character (-) between the E and the number and the number is not zero, or else ignoring a U+002B PLUS SIGN character (+) between the E and the number if there is one). If there is no E, then the exponent is treated as zero.
The Infinity and Not-a-Number (NaN) values are not valid floating point numbers.
A valid list of integers is a number of valid integers separated by U+002C COMMA characters, with no other characters (e.g. no space characters). In addition, there might be restrictions on the number of integers that can be given, or on the range of values allowed.
In the algorithms below, the number of days in month month of year year is: 31 if month is 1, 3, 5, 7, 8, 10, or 12; 30 if month is 4, 6, 9, or 11; 29 if month is 2 and year is a number divisible by 400, or if year is a number divisible by 4 but not by 100; and 28 otherwise. This takes into account leap years in the Gregorian calendar. [GREGORIAN]
The digits in the date and time syntaxes defined in this section must be characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), used to express numbers in base ten.
A month consists of a specific proleptic Gregorian date with no time-zone information and no date information beyond a year and a month. [GREGORIAN]
A string is a valid month string representing a year year and month month if it consists of the following components in the given order:
A date consists of a specific proleptic Gregorian date with no time-zone information, consisting of a year, a month, and a day. [GREGORIAN]
A string is a valid date string representing a year year, month month, and day day if it consists of the following components in the given order:
A time consists of a specific time with no time-zone information, consisting of an hour, a minute, a second, and a fraction of a second.
A string is a valid time string representing an hour hour, a minute minute, and a second second if it consists of the following components in the given order:
The second component cannot be 60 or 61; leap seconds cannot be represented.
A local date and time consists of a specific proleptic Gregorian date, consisting of a year, a month, and a day, and a time, consisting of an hour, a minute, a second, and a fraction of a second, but expressed without a time zone. [GREGORIAN]
A string is a valid local date and time string representing a date and time if it consists of the following components in the given order:
A global date and time consists of a specific proleptic Gregorian date, consisting of a year, a month, and a day, and a time, consisting of an hour, a minute, a second, and a fraction of a second, expressed with a time-zone offset, consisting of a signed number of hours and minutes. [GREGORIAN]
A string is a valid global date and time string representing a date, time, and a time-zone offset if it consists of the following components in the given order:
This format allows for time-zone offsets from -23:59 to +23:59. In practice, however, the range of offsets of actual time zones is -12:00 to +14:00, and the minutes component of offsets of actual time zones is always either 00, 30, or 45.
Times in dates before the formation of UTC in the mid twentieth century must be expressed and interpreted in terms of UT1 (contemporary Earth solar time at the 0° longitude), not UTC (the approximation of UT1 that ticks in SI seconds). Time before the formation of time zones must be expressed and interpeted as UT1 times with explicit time zones that approximate the contemporary difference between the appropriate local time and the time observed at the location of Greenwich, London.
The following are some examples of dates written as valid global date and time strings.
0037-12-13T00:00Z
"1979-10-14T12:00:00.001-04:00
"8592-01-01T02:09+02:09
"Several things are notable about these dates:
A week consists of a week-year number and a week number representing a seven-day period starting on a Monday. Each week-year in this calendaring system has either 52 or 53 such seven-day periods, as defined below. The seven-day period starting on the Gregorian date Monday December 29th 1969 (1969-12-29) is defined as week number 1 in week-year 1970. Consecutive weeks are numbered sequentially. The week before the number 1 week in a week-year is the last week in the previous week-year, and vice versa. [GREGORIAN]
A week-year with a number year has 53 weeks if it corresponds to either a year year in the proleptic Gregorian calendar that has a Thursday as its first day (January 1st), or a year year in the proleptic Gregorian calendar that has a Wednesday as its first day (January 1st) and where year is a number divisible by 400, or a number divisible by 4 but not by 100. All other week-years have 52 weeks.
The week number of the last day of a week-year with 53 weeks is 53; the week number of the last day of a week-year with 52 weeks is 52.
The week-year number of a particular day can be different than the number of the year that contains that day in the proleptic Gregorian calendar. The first week in a week-year y is the week that contains the first Thursday of the Gregorian year y.
A string is a valid week string representing a week-year year and week week if it consists of the following components in the given order:
A string is a valid date or time string if it is also one of the following:
A string is a valid date or time string in content if it consists of zero or more White_Space characters, followed by a valid date or time string, followed by zero or more further White_Space characters.
A string is a valid date string with optional time if it is also one of the following:
A string is a valid date string in content with optional time if it consists of zero or more White_Space characters, followed by a valid date string with optional time, followed by zero or more further White_Space characters.
A simple color consists of three 8-bit numbers in the range 0..255, representing the red, green, and blue components of the color respectively, in the sRGB color space. [SRGB]
A string is a valid simple color if it is exactly seven characters long, and the first character is a U+0023 NUMBER SIGN character (#), and the remaining six characters are all in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), U+0041 LATIN CAPITAL LETTER A to U+0046 LATIN CAPITAL LETTER F, U+0061 LATIN SMALL LETTER A to U+0066 LATIN SMALL LETTER F, with the first two digits representing the red component, the middle two digits representing the green component, and the last two digits representing the blue component, in hexadecimal.
A string is a valid lowercase simple color if it is a valid simple color and doesn't use any characters in the range U+0041 LATIN CAPITAL LETTER A to U+0046 LATIN CAPITAL LETTER F.
A set of space-separated tokens is a string containing zero or more words (known as tokens) separated by one or more space characters, where words consist of any string of one or more characters, none of which are space characters.
A string containing a set of space-separated tokens may have leading or trailing space characters.
An unordered set of unique space-separated tokens is a set of space-separated tokens where none of the tokens are duplicated.
An ordered set of unique space-separated tokens is a set of space-separated tokens where none of the tokens are duplicated but where the order of the tokens is meaningful.
Sets of space-separated tokens sometimes have a defined set of allowed values. When a set of allowed values is defined, the tokens must all be from that list of allowed values; other values are non-conforming. If no such set of allowed values is provided, then all values are conforming.
How tokens in a set of space-separated tokens are to be compared (e.g. case-sensitively or not) is defined on a per-set basis.
A set of comma-separated tokens is a string containing zero or more tokens each separated from the next by a single U+002C COMMA character (,), where tokens consist of any string of zero or more characters, neither beginning nor ending with space characters, nor containing any U+002C COMMA characters (,), and optionally surrounded by space characters.
For instance, the string " a ,b,,d d
" consists of four tokens: "a", "b", the empty string, and "d d". Leading and trailing whitespace around each token doesn't count as part of the token, and the empty string can be a token.
Sets of comma-separated tokens sometimes have further restrictions on what consists a valid token. When such restrictions are defined, the tokens must all fit within those restrictions; other values are non-conforming. If no such restrictions are specified, then all values are conforming.
A valid hash-name reference to an element of type type is a string consisting of a U+0023 NUMBER SIGN character (#) followed by a string which exactly matches the value of the name
attribute of an element with type type in the document.
A string is a valid media query if it matches the media_query_list
production of the Media Queries specification. [MQ]
A string matches the environment of the user if it is the empty string, a string consisting of only space characters, or is a media query that matches the user's environment according to the definitions given in the Media Queries specification. [MQ]
This specification defines the term URL, and defines various algorithms for dealing with URLs, because for historical reasons the rules defined by the URI and IRI specifications are not a complete description of what HTML user agents need to implement to be compatible with Web content.
The term "URL" in this specification is used in a manner distinct from the precise technical meaning it is given in RFC 3986. Readers familiar with that RFC will find it easier to read this specification if they pretend the term "URL" as used herein is really called something else altogether. This is a willful violation of RFC 3986. [RFC3986]
A URL is a string used to identify a resource.
A URL is a valid URL if at least one of the following conditions holds:
The URL is a valid IRI reference and it has no query component. [RFC3987]
The URL is a valid IRI reference and its query component contains no unescaped non-ASCII characters. [RFC3987]
The URL is a valid IRI reference and the character encoding of the URL's Document
is UTF-8 or UTF-16. [RFC3987]
A string is a valid non-empty URL if it is a valid URL but it is not the empty string.
A string is a valid URL potentially surrounded by spaces if, after stripping leading and trailing whitespace from it, it is a valid URL.
A string is a valid non-empty URL potentially surrounded by spaces if, after stripping leading and trailing whitespace from it, it is a valid non-empty URL.
This specification defines the URL about:legacy-compat
as a reserved, though unresolvable, about:
URI, for use in DOCTYPEs in HTML documents when needed for compatibility with XML tools. [ABOUT]
This specification defines the URL about:srcdoc
as a reserved, though unresolvable, about:
URI, that is used as the document's address of iframe
srcdoc
documents. [ABOUT]
Resolving a URL is the process of taking a relative URL and obtaining the absolute URL that it implies.
A URL is an absolute URL if resolving it results in the same output regardless of what it is resolved relative to, and that output is not a failure.
An absolute URL is a hierarchical URL if, when resolved and then parsed, there is a character immediately after the <scheme> component and it is a U+002F SOLIDUS character (/).
An absolute URL is an authority-based URL if, when resolved and then parsed, there are two characters immediately after the <scheme> component and they are both U+002F SOLIDUS characters (//).
An interface that has a complement of URL decomposition IDL attributes has seven attributes with the following definitions:
attribute DOMString protocol; attribute DOMString host; attribute DOMString hostname; attribute DOMString port; attribute DOMString pathname; attribute DOMString search; attribute DOMString hash;
protocol
[ = value ]Returns the current scheme of the underlying URL.
Can be set, to change the underlying URL's scheme.
host
[ = value ]Returns the current host and port (if it's not the default port) in the underlying URL.
Can be set, to change the underlying URL's host and port.
The host and the port are separated by a colon. The port part, if omitted, will be assumed to be the current scheme's default port.
hostname
[ = value ]Returns the current host in the underlying URL.
Can be set, to change the underlying URL's host.
port
[ = value ]Returns the current port in the underlying URL.
Can be set, to change the underlying URL's port.
pathname
[ = value ]Returns the current path in the underlying URL.
Can be set, to change the underlying URL's path.
search
[ = value ]Returns the current query component in the underlying URL.
Can be set, to change the underlying URL's query component.
hash
[ = value ]Returns the current fragment identifier in the underlying URL.
Can be set, to change the underlying URL's fragment identifier.
The table below demonstrates how the getter for search
results in different results depending on the exact original syntax of the URL:
Input URL | search value |
Explanation |
---|---|---|
http://example.com/ |
empty string | No <query> component in input URL. |
http://example.com/? |
? |
There is a <query> component, but it is empty. |
http://example.com/?test |
?test |
The <query> component has the value "test ". |
http://example.com/?test# |
?test |
The (empty) <fragment> component is not part of the <query> component. |
The following table is similar; it provides a list of what each of the URL decomposition IDL attributes returns for a given input URL.
Input | protocol |
host |
hostname |
port |
pathname |
search |
hash |
---|---|---|---|---|---|---|---|
http://example.com/carrot#question%3f |
http: |
example.com |
example.com |
(empty string) | /carrot |
(empty string) | #question%3f |
https://www.example.com:4443? |
https: |
www.example.com:4443 |
www.example.com |
4443 |
/ |
? |
(empty string) |
Some IDL attributes are defined to reflect a particular content attribute. This means that on getting, the IDL attribute returns the current value of the content attribute, and on setting, the IDL attribute changes the value of the content attribute to the given value.
The HTMLCollection
, HTMLAllCollection
, HTMLFormControlsCollection
, HTMLOptionsCollection
, interfaces represent various lists of DOM nodes. Collectively, objects implementing these interfaces are called collections.
When a collection is created, a filter and a root are associated with the collection.
For example, when the HTMLCollection
object for the document.images
attribute is created, it is associated with a filter that selects only img
elements, and rooted at the root of the document.
The collection then represents a live view of the subtree rooted at the collection's root, containing only nodes that match the given filter. The view is linear.
The HTMLCollection
interface represents a generic collection of elements.
interface HTMLCollection { readonly attribute unsigned long length; caller getter Element item(in unsigned long index); caller getter object namedItem(in DOMString name); // only returns Element };
length
Returns the number of elements in the collection.
item
(index)Returns the item with index index from the collection. The items are sorted in tree order.
Returns null if index is out of range.
namedItem
(name)Returns the first item with ID or name name from the collection.
Returns null if no element with that ID or name could be found.
Only a
, applet
, area
, embed
, form
, frame
, frameset
, iframe
, img
, and object
elements can have a name for the purpose of this method; their name is given by the value of their name
attribute.
The HTMLAllCollection
interface represents a generic collection of elements just like HTMLCollection
, with the exception that its namedItem()
method returns an HTMLAllCollection
object when there are multiple matching elements.
interface HTMLAllCollection : HTMLCollection { // inherits length and item() caller getter object namedItem(in DOMString name); // overrides inherited namedItem() HTMLAllCollection tags(in DOMString tagName); };
length
Returns the number of elements in the collection.
item
(index)Returns the item with index index from the collection. The items are sorted in tree order.
Returns null if index is out of range.
namedItem
(name)namedItem
(name)Returns the item with ID or name name from the collection.
If there are multiple matching items, then an HTMLAllCollection
object containing all those elements is returned.
Returns null if no element with that ID or name could be found.
Only a
, applet
, area
, embed
, form
, frame
, frameset
, iframe
, img
, and object
elements can have a name for the purpose of this method; their name is given by the value of their name
attribute.
tags
(tagName)Returns a collection that is a filtered view of the current collection, containing only elements with the given tag name.
The HTMLFormControlsCollection
interface represents a collection of listed elements in form
and fieldset
elements.
interface HTMLFormControlsCollection : HTMLCollection { // inherits length and item() caller getter object namedItem(in DOMString name); // overrides inherited namedItem() }; interface RadioNodeList : NodeList { attribute DOMString value; };
length
Returns the number of elements in the collection.
item
(index)Returns the item with index index from the collection. The items are sorted in tree order.
Returns null if index is out of range.
namedItem
(name)namedItem
(name)Returns the item with ID or name
name from the collection.
If there are multiple matching items, then a RadioNodeList
object containing all those elements is returned.
Returns null if no element with that ID or name
could be found.
Returns the value of the first checked radio button represented by the object.
Can be set, to check the first radio button with the given value represented by the object.
The HTMLOptionsCollection
interface represents a list of option
elements. It is always rooted on a select
element and has attributes and methods that manipulate that element's descendants.
interface HTMLOptionsCollection : HTMLCollection { // inherits item() attribute unsigned long length; // overrides inherited length caller getter object namedItem(in DOMString name); // overrides inherited namedItem() void add(in HTMLElement element, in optional HTMLElement before); void add(in HTMLElement element, in long before); void remove(in long index); attribute long selectedIndex; };
length
[ = value ]Returns the number of elements in the collection.
When set to a smaller number, truncates the number of option
elements in the corresponding container.
When set to a greater number, adds new blank option
elements to that container.
item
(index)Returns the item with index index from the collection. The items are sorted in tree order.
Returns null if index is out of range.
namedItem
(name)namedItem
(name)Returns the item with ID or name
name from the collection.
If there are multiple matching items, then a NodeList
object containing all those elements is returned.
Returns null if no element with that ID could be found.
add
(element [, before ] )Inserts element before the node given by before.
The before argument can be a number, in which case element is inserted before the item with that number, or an element from the collection, in which case element is inserted before that element.
If before is omitted, null, or a number out of range, then element will be added at the end of the list.
This method will throw a HIERARCHY_REQUEST_ERR
exception if element is an ancestor of the element into which it is to be inserted. If element is not an option
or optgroup
element, then the method does nothing.
selectedIndex
[ = value ]Returns the index of the first selected item, if any, or −1 if there is no selected item.
Can be set, to change the selection.
The DOMTokenList
interface represents an interface to an underlying string that consists of a set of space-separated tokens.
DOMTokenList
objects are always case-sensitive, even when the underlying string might ordinarily be treated in a case-insensitive manner.
interface DOMTokenList { readonly attribute unsigned long length; getter DOMString item(in unsigned long index); boolean contains(in DOMString token); void add(in DOMString token); void remove(in DOMString token); boolean toggle(in DOMString token); stringifier DOMString (); };
length
Returns the number of tokens in the string.
item
(index)Returns the token with index index. The tokens are returned in the order they are found in the underlying string.
Returns null if index is out of range.
contains
(token)Returns true if the token is present; false otherwise.
Throws a SYNTAX_ERR
exception if token is empty.
Throws an INVALID_CHARACTER_ERR
exception if token contains any spaces.
add
(token)Adds token, unless it is already present.
Throws a SYNTAX_ERR
exception if token is empty.
Throws an INVALID_CHARACTER_ERR
exception if token contains any spaces.
remove
(token)Removes token if it is present.
Throws a SYNTAX_ERR
exception if token is empty.
Throws an INVALID_CHARACTER_ERR
exception if token contains any spaces.
toggle
(token)Adds token if it is not present, or removes it if it is. Returns true if token is now present (it was added); returns false if it is not (it was removed).
Throws a SYNTAX_ERR
exception if token is empty.
Throws an INVALID_CHARACTER_ERR
exception if token contains any spaces.
A DOMTokenList
object must stringify to the value of the DOMTokenList
object's underlying string.
The DOMSettableTokenList
interface is the same as the DOMTokenList
interface, except that it allows the underlying string to be directly changed.
interface DOMSettableTokenList : DOMTokenList { attribute DOMString value; };
value
Returns the underlying string.
Can be set, to change the underlying string.
The DOMStringMap
interface represents a set of name-value pairs. It exposes these using the scripting language's native mechanisms for property access.
The dataset
attribute on elements exposes the data-*
attributes on the element.
Given the following fragment and elements with similar constructions:
<img class="tower" id="tower5" data-x="12" data-y="5" data-ai="robotarget" data-hp="46" data-ability="flames" src="towers/rocket.png alt="Rocket Tower">
...one could imagine a function splashDamage()
that takes some arguments, the first of which is the element to process:
function splashDamage(node, x, y, damage) { if (node.classList.contains('tower') && // checking the 'class' attribute node.dataset.x == x && // reading the 'data-x' attribute node.dataset.y == y) { // reading the 'data-y' attribute var hp = parseInt(node.dataset.hp); // reading the 'data-hp' attribute hp = hp - damage; if (hp < 0) { hp = 0; node.dataset.ai = 'dead'; // setting the 'data-ai' attribute delete node.dataset.ability; // removing the 'data-ability' attribute } node.dataset.hp = hp; // setting the 'data-hp' attribute } }
DOM3 Core defines mechanisms for checking for interface support, and for obtaining implementations of interfaces, using feature strings. [DOMCORE]
Authors are strongly discouraged from using these, as they are notoriously unreliable and imprecise. Authors are encouraged to rely on explicit feature testing or the graceful degradation behavior intrinsic to some of the features in this specification.
The following are DOMException
codes. [DOMCORE]
INDEX_SIZE_ERR
DOMSTRING_SIZE_ERR
HIERARCHY_REQUEST_ERR
WRONG_DOCUMENT_ERR
INVALID_CHARACTER_ERR
NO_DATA_ALLOWED_ERR
NO_MODIFICATION_ALLOWED_ERR
NOT_FOUND_ERR
NOT_SUPPORTED_ERR
INUSE_ATTRIBUTE_ERR
INVALID_STATE_ERR
SYNTAX_ERR
INVALID_MODIFICATION_ERR
NAMESPACE_ERR
INVALID_ACCESS_ERR
VALIDATION_ERR
TYPE_MISMATCH_ERR
SECURITY_ERR
NETWORK_ERR
ABORT_ERR
URL_MISMATCH_ERR
QUOTA_EXCEEDED_ERR
TIMEOUT_ERR
DATA_CLONE_ERR
The HTML namespace is: http://www.w3.org/1999/xhtml
The MathML namespace is: http://www.w3.org/1998/Math/MathML
The SVG namespace is: http://www.w3.org/2000/svg
The XLink namespace is: http://www.w3.org/1999/xlink
The XML namespace is: http://www.w3.org/XML/1998/namespace
The XMLNS namespace is: http://www.w3.org/2000/xmlns/
Data mining tools and other user agents that perform operations on content without running scripts, evaluating CSS or XPath expressions, or otherwise exposing the resulting DOM to arbitrary content, may "support namespaces" by just asserting that their DOM node analogues are in certain namespaces, without actually exposing the above strings.
In the HTML syntax, namespace prefixes and namespace declarations do not have the same effect as in XML. For instance, the colon has no special meaning in HTML element names.
Every XML and HTML document in an HTML UA is represented by a Document
object. [DOMCORE]
The document's address is an absolute URL that is set when the Document
is created. The document's current address is an absolute URL that can change during the lifetime of the Document
, for example when the user navigates to a fragment
identifier on the page or when the pushState()
method is called with a new URL.
Interactive user agents typically expose the document's current address in their user interface.
When a Document
is created by a script using the createDocument()
or createHTMLDocument()
APIs, the document's address is the same as the document's address of the script's document.
Document
objects are assumed to be XML documents unless they are flagged as being HTML documents when they are created. Whether a document is an HTML document or an XML document affects the behavior of certain APIs and the case-sensitivity of some selectors.
Each Document
object has a reload override flag that is originally unset. The flag is set by the document.open()
and document.write()
methods in certain situations. When the flag is set, the Document
also has a reload override buffer which is a Unicode string that is used as the source of the document when it is reloaded.
When the user agent is to perform an overridden reload, it must act as follows:
Let source be the value of the browsing context's active document's reload override buffer.
Navigate the browsing context to a resource whose source is source, with replacement enabled. When the navigate algorithm creates a Document
object for this purpose, set that Document
's reload override flag and
set its reload override buffer to source.
All Document
objects (in user agents implementing this specification) also implement the HTMLDocument
interface, available using binding-specific methods. (This is the case whether or not the document in question is an HTML document or indeed whether it contains any HTML elements at all.) Document
objects also implement the document-level interface of any other namespaces that the UA supports.
For example, if an HTML implementation also supports SVG, then the Document
object implements both HTMLDocument
and SVGDocument
.
Because the HTMLDocument
interface is now obtained using binding-specific casting methods instead of simply being the primary interface of the document object, it is no longer defined as inheriting from Document
.
[OverrideBuiltins] interface HTMLDocument { // resource metadata management [PutForwards=href] readonly attribute Location location; readonly attribute DOMString URL; attribute DOMString domain; readonly attribute DOMString referrer; attribute DOMString cookie; readonly attribute DOMString lastModified; readonly attribute DOMString compatMode; attribute DOMString charset; readonly attribute DOMString characterSet; readonly attribute DOMString defaultCharset; readonly attribute DOMString readyState; // DOM tree accessors getter any (in DOMString name); attribute DOMString title; attribute DOMString dir; attribute HTMLElement body; readonly attribute HTMLHeadElement head; readonly attribute HTMLCollection images; readonly attribute HTMLCollection embeds; readonly attribute HTMLCollection plugins; readonly attribute HTMLCollection links; readonly attribute HTMLCollection forms; readonly attribute HTMLCollection scripts; NodeList getElementsByName(in DOMString elementName); NodeList getElementsByClassName(in DOMString classNames); // dynamic markup insertion attribute DOMString innerHTML; HTMLDocument open(in optional DOMString type, in optional DOMString replace); WindowProxy open(in DOMString url, in DOMString name, in DOMString features, in optional boolean replace); void close(); void write(in DOMString... text); void writeln(in DOMString... text); // user interaction readonly attribute WindowProxy defaultView; readonly attribute Element activeElement; boolean hasFocus(); attribute DOMString designMode; boolean execCommand(in DOMString commandId); boolean execCommand(in DOMString commandId, in boolean showUI); boolean execCommand(in DOMString commandId, in boolean showUI, in DOMString value); boolean queryCommandEnabled(in DOMString commandId); boolean queryCommandIndeterm(in DOMString commandId); boolean queryCommandState(in DOMString commandId); boolean queryCommandSupported(in DOMString commandId); DOMString queryCommandValue(in DOMString commandId); readonly attribute HTMLCollection commands; // event handler IDL attributes attribute Function onabort; attribute Function onblur; attribute Function oncanplay; attribute Function oncanplaythrough; attribute Function onchange; attribute Function onclick; attribute Function oncontextmenu; attribute Function oncuechange; attribute Function ondblclick; attribute Function ondrag; attribute Function ondragend; attribute Function ondragenter; attribute Function ondragleave; attribute Function ondragover; attribute Function ondragstart; attribute Function ondrop; attribute Function ondurationchange; attribute Function onemptied; attribute Function onended; attribute Function onerror; attribute Function onfocus; attribute Function oninput; attribute Function oninvalid; attribute Function onkeydown; attribute Function onkeypress; attribute Function onkeyup; attribute Function onload; attribute Function onloadeddata; attribute Function onloadedmetadata; attribute Function onloadstart; attribute Function onmousedown; attribute Function onmousemove; attribute Function onmouseout; attribute Function onmouseover; attribute Function onmouseup; attribute Function onmousewheel; attribute Function onpause; attribute Function onplay; attribute Function onplaying; attribute Function onprogress; attribute Function onratechange; attribute Function onreadystatechange; attribute Function onreset; attribute Function onscroll; attribute Function onseeked; attribute Function onseeking; attribute Function onselect; attribute Function onshow; attribute Function onstalled; attribute Function onsubmit; attribute Function onsuspend; attribute Function ontimeupdate; attribute Function onvolumechange; attribute Function onwaiting; }; Document implements HTMLDocument;
Since the HTMLDocument
interface holds methods and attributes related to a number of disparate features, the members of this interface are described in various different sections.
User agents raise a SECURITY_ERR
exception whenever any of the members of an HTMLDocument
object are accessed by scripts whose effective script origin is not the same as the Document
's effective script origin.
URL
Returns the document's address.
referrer
Returns the address of the Document
from which the user navigated to this one, unless it was blocked or there was no such document, in which case it returns the empty string.
The noreferrer
link type can be used to block the referrer.
In the case of HTTP, the referrer
IDL attribute will match the Referer
(sic) header that was sent when fetching the current page.
Typically user agents are configured to not report referrers in the case where the referrer uses an encrypted protocol and the current page does not (e.g. when navigating from an https:
page to an http:
page).
cookie
[ = value ]Returns the HTTP cookies that apply to the Document
. If there are no cookies or cookies can't be applied to this resource, the empty string will be returned.
Can be set, to add a new cookie to the element's set of HTTP cookies.
If the contents are sandboxed into a unique origin (in an iframe
with the sandbox
attribute) or the resource was labeled as text/html-sandboxed
, a SECURITY_ERR
exception will be thrown on getting and setting.
lastModified
Returns the date of the last modification to the document, as reported by the server, in the form "MM/DD/YYYY hh:mm:ss
", in the user's local time zone.
If the last modification date is not known, the current time is returned instead.
compatMode
In a conforming document, returns the string "CSS1Compat
". (In quirks mode documents, returns the string "BackCompat
", but a conforming document can never trigger quirks mode.)
charset
[ = value ]Returns the document's character encoding.
Can be set, to dynamically change the document's character encoding.
New values that are not IANA-registered aliases supported by the user agent are ignored.
characterSet
Returns the document's character encoding.
defaultCharset
Returns what might be the user agent's default character encoding. (The user agent might return another character encoding altogether, e.g. to protect the user's privacy, or if the user agent doesn't use a single default encoding.)
readyState
Returns "loading" while the Document
is loading, "interactive" once it is finished parsing but still loading sub-resources, and "complete" once it has loaded.
The readystatechange
event fires on the Document
object when this value changes.
The html
element of a document is the document's root element, if there is one and it's an html
element, or null otherwise.
head
Returns the head
element.
The head
element of a document is the first head
element that is a child of the html
element, if there is one, or null otherwise.
title
[ = value ]Returns the document's title, as given by the title
element.
Can be set, to update the document's title. If there is no head
element, the new value is ignored.
In SVG documents, the SVGDocument
interface's title
attribute takes precedence.
The title
element of a document is the first title
element in the document (in tree order), if there is one, or null otherwise.
body
[ = value ]Returns the body element.
Can be set, to replace the body element.
If the new value is not a body
or frameset
element, this will throw a HIERARCHY_REQUEST_ERR
exception.
The body element of a document is the first child of the html
element that is either a body
element or a frameset
element. If there is no such element, it is null.
images
Returns an HTMLCollection
of the img
elements in the Document
.
embeds
plugins
Return an HTMLCollection
of the embed
elements in the Document
.
links
Returns an HTMLCollection
of the a
and area
elements in the Document
that have href
attributes.
forms
Return an HTMLCollection
of the form
elements in the Document
.
scripts
Return an HTMLCollection
of the script
elements in the Document
.
getElementsByName
(name)Returns a NodeList
of elements in the Document
that have a name
attribute with the value name.
getElementsByClassName(classes)
getElementsByClassName(classes)
Returns a NodeList
of the elements in the object on which the method was invoked (a Document
or an Element
) that have all the classes given by classes.
The classes argument is interpreted as a space-separated list of classes.
HTML, SVG, and MathML elements define which classes they are in by having an attribute with no namespace with the name class
containing a space-separated list of classes to which the element belongs. Other specifications may also allow elements in their namespaces to be labeled as being in specific classes.
Given the following XHTML fragment:
<div id="example"> <p id="p1" class="aaa bbb"/> <p id="p2" class="aaa ccc"/> <p id="p3" class="bbb ccc"/> </div>
A call to document.getElementById('example').getElementsByClassName('aaa')
would return a NodeList
with the two paragraphs p1
and p2
in it.
A call to getElementsByClassName('ccc bbb')
would only return one node, however, namely p3
. A call to document.getElementById('example').getElementsByClassName('bbb ccc ')
would return the same thing.
A call to getElementsByClassName('aaa,bbb')
would return no nodes; none of the elements above are in the "aaa,bbb" class.
The dir
attribute on the HTMLDocument
interface is defined along with the dir
content attribute.
XML documents can be created from script using the createDocument()
method on the DOMImplementation
interface.
HTML documents can be created using the createHTMLDocument()
method:
[Supplemental, NoInterfaceObject] interface DOMHTMLImplementation { Document createHTMLDocument(in DOMString title); }; DOMImplementation implements DOMHTMLImplementation;
implementation
. createHTMLDocument
( title )Returns a new Document
, with a basic DOM already constructed with an appropriate title
element.
Elements, attributes, and attribute values in HTML are defined (by this specification) to have certain meanings (semantics). For example, the ol
element represents an ordered list, and the lang
attribute represents the language of the content.
Authors must not use elements, attributes, or attribute values for purposes other than their appropriate intended semantic purpose. Authors must not use elements, attributes, or attribute values that are not permitted by this specification or other applicable specifications.
For example, the following document is non-conforming, despite being syntactically correct:
<!DOCTYPE HTML> <html lang="en-GB"> <head> <title> Demonstration </title> </head> <body> <table> <tr> <td> My favourite animal is the cat. </td> </tr> <tr> <td> —<a href="http://example.org/~ernest/"><cite>Ernest</cite></a>, in an essay from 1992 </td> </tr> </table> </body> </html>
...because the data placed in the cells is clearly not tabular data (and the cite
element mis-used). A corrected version of this document might be:
<!DOCTYPE HTML> <html lang="en-GB"> <head> <title> Demonstration </title> </head> <body> <blockquote> <p> My favourite animal is the cat. </p> </blockquote> <p> —<a href="http://example.org/~ernest/">Ernest</a>, in an essay from 1992 </p> </body> </html>
This next document fragment, intended to represent the heading of a corporate site, is similarly non-conforming because the second line is not intended to be a heading of a subsection, but merely a subheading or subtitle (a subordinate heading for the same section).
<body> <h1>ABC Company</h1> <h2>Leading the way in widget design since 1432</h2> ...
The hgroup
element is intended for these kinds of situations:
<body> <hgroup> <h1>ABC Company</h1> <h2>Leading the way in widget design since 1432</h2> </hgroup> ...
In the next example, there is a non-conforming attribute value ("carpet") and a non-conforming attribute ("texture"), which is not permitted by this specification:
<label>Carpet: <input type="carpet" name="c" texture="deep pile"></label>
Here would be an alternative and correct way to mark this up:
<label>Carpet: <input type="text" class="carpet" name="c" data-texture="deep pile"></label>
Through scripting and using other mechanisms, the values of attributes, text, and indeed the entire structure of the document may change dynamically while a user agent is processing it. The semantics of a document at an instant in time are those represented by the state of the document at that instant in time, and the semantics of a document can therefore change over time. User agents update their presentation of the document as this occurs.
HTML has a progress
element that describes a progress bar. If its "value" attribute is dynamically updated by a script, the UA would update the rendering to show the progress changing.
The nodes representing HTML elements in the DOM implement, and expose to scripts, the interfaces listed for them in the relevant sections of this specification. This includes HTML elements in XML documents, even when those documents are in another context (e.g. inside an XSLT transform).
Elements in the DOM represent things; that is, they have intrinsic meaning, also known as semantics.
For example, an ol
element represents an ordered list.
The basic interface, from which all the HTML elements' interfaces inherit, is the HTMLElement
interface.
interface HTMLElement : Element { // DOM tree accessors NodeList getElementsByClassName(in DOMString classNames); // dynamic markup insertion attribute DOMString innerHTML; attribute DOMString outerHTML; void insertAdjacentHTML(in DOMString position, in DOMString text); // metadata attributes attribute DOMString id; attribute DOMString title; attribute DOMString lang; attribute DOMString dir; attribute DOMString className; readonly attribute DOMTokenList classList; readonly attribute DOMStringMap dataset; // user interaction attribute boolean hidden; void click(); attribute long tabIndex; void focus(); void blur(); attribute DOMString accessKey; readonly attribute DOMString accessKeyLabel; attribute boolean draggable; [PutForwards=value] attribute DOMSettableTokenList dropzone; attribute DOMString contentEditable; readonly attribute boolean isContentEditable; attribute HTMLMenuElement contextMenu; attribute boolean spellcheck; // command API readonly attribute DOMString commandType; readonly attribute DOMString label; readonly attribute DOMString icon; readonly attribute boolean disabled; readonly attribute boolean checked; // styling readonly attribute CSSStyleDeclaration style; // event handler IDL attributes attribute Function onabort; attribute Function onblur; attribute Function oncanplay; attribute Function oncanplaythrough; attribute Function onchange; attribute Function onclick; attribute Function oncontextmenu; attribute Function oncuechange; attribute Function ondblclick; attribute Function ondrag; attribute Function ondragend; attribute Function ondragenter; attribute Function ondragleave; attribute Function ondragover; attribute Function ondragstart; attribute Function ondrop; attribute Function ondurationchange; attribute Function onemptied; attribute Function onended; attribute Function onerror; attribute Function onfocus; attribute Function oninput; attribute Function oninvalid; attribute Function onkeydown; attribute Function onkeypress; attribute Function onkeyup; attribute Function onload; attribute Function onloadeddata; attribute Function onloadedmetadata; attribute Function onloadstart; attribute Function onmousedown; attribute Function onmousemove; attribute Function onmouseout; attribute Function onmouseover; attribute Function onmouseup; attribute Function onmousewheel; attribute Function onpause; attribute Function onplay; attribute Function onplaying; attribute Function onprogress; attribute Function onratechange; attribute Function onreadystatechange; attribute Function onreset; attribute Function onscroll; attribute Function onseeked; attribute Function onseeking; attribute Function onselect; attribute Function onshow; attribute Function onstalled; attribute Function onsubmit; attribute Function onsuspend; attribute Function ontimeupdate; attribute Function onvolumechange; attribute Function onwaiting; }; interface HTMLUnknownElement : HTMLElement { };
The HTMLElement
interface holds methods and attributes related to a number of disparate features, and the members of this interface are therefore described in various different sections of this specification.
The following attributes are common to and may be specified on all HTML elements:
accesskey
class
contenteditable
contextmenu
dir
draggable
dropzone
id
lang
spellcheck
style
tabindex
title
The following event handler content attributes may be specified on any HTML element:
onabort
onblur
*oncanplay
oncanplaythrough
onchange
onclick
oncontextmenu
oncuechange
ondblclick
ondrag
ondragend
ondragenter
ondragleave
ondragover
ondragstart
ondrop
ondurationchange
onemptied
onended
onerror
*onfocus
*oninput
oninvalid
onkeydown
onkeypress
onkeyup
onload
*onloadeddata
onloadedmetadata
onloadstart
onmousedown
onmousemove
onmouseout
onmouseover
onmouseup
onmousewheel
onpause
onplay
onplaying
onprogress
onratechange
onreadystatechange
onreset
onscroll
*onseeked
onseeking
onselect
onshow
onstalled
onsubmit
onsuspend
ontimeupdate
onvolumechange
onwaiting
The attributes marked with an asterisk have a different meaning when specified on body
elements as those elements expose event handlers of the Window
object with the same names.
While these attributes apply to all elements, they are not useful on all elements. For example, only media elements will ever receive a volumechange
event fired by the user agent.
Custom data attributes (e.g. data-foldername
or data-msgid
) can be specified on any HTML element, to store custom data specific to the page.
In HTML documents, elements in the HTML namespace may have an xmlns
attribute specified, if, and only if, it has the exact value "http://www.w3.org/1999/xhtml
". This does not apply to XML documents.
In HTML, the xmlns
attribute has absolutely no effect. It is basically a talisman. It is allowed merely to make migration to and from XHTML mildly easier. When parsed by an HTML parser, the attribute ends up in no namespace, not the "http://www.w3.org/2000/xmlns/
" namespace like namespace declaration attributes in XML do.
In XML, an xmlns
attribute is part of the namespace declaration mechanism, and an element cannot actually have an xmlns
attribute in no namespace specified.
The XML specification also allows the use of the xml:space
attribute in the XML namespace on any element in an XML document. This attribute has no effect on HTML elements, as the default behavior in HTML is to preserve whitespace. [XML]
There is no way to serialize the xml:space
attribute on HTML elements in the text/html
syntax.
To enable assistive technology products to expose a more fine-grained interface than is otherwise possible with HTML elements and attributes, a set of annotations for assistive technology products can be specified (the ARIA role
and aria-*
attributes).
id
attributeThe id
attribute specifies its element's unique identifier (ID). The value must be unique amongst all the IDs in the element's home subtree and must contain at least one character. The value must not contain any space characters.
An element's unique identifier can be used for a variety of purposes, most notably as a way to link to specific parts of a document using fragment identifiers, as a way to target an element when scripting, and as a way to style a specific element from CSS.
The id
IDL attribute must reflect the id
content attribute.
title
attributeThe title
attribute represents advisory information for the element, such as would be appropriate for a tooltip. On a link, this could be the title or a description of the target resource; on an image, it could be the image credit or a description of the image; on a paragraph, it could be a footnote or commentary on the text; on a citation, it could be further information about the source; and so forth. The value is text.
If this attribute is omitted from an element, then it implies that the title
attribute of the nearest ancestor HTML element with a title
attribute set is also relevant to this element. Setting the attribute overrides this, explicitly stating that the advisory information of any ancestors is not relevant to this element. Setting the attribute to the empty string indicates that the element has no advisory information.
If the title
attribute's value contains U+000A LINE FEED (LF) characters, the content is split into multiple lines. Each U+000A LINE FEED (LF) character represents a line break.
Caution is advised with respect to the use of newlines in title
attributes.
For instance, the following snippet actually defines an abbreviation's expansion with a line break in it:
<p>My logs show that there was some interest in <abbr title="Hypertext Transport Protocol">HTTP</abbr> today.</p>
Some elements, such as link
, abbr
, and input
, define additional semantics for the title
attribute beyond the semantics described above.
The title
IDL attribute must reflect the title
content attribute.
lang
and xml:lang
attributesThe lang
attribute (in no namespace) specifies the primary language for the element's contents and for any of the element's attributes that contain text. Its value must be a valid BCP 47 language tag, or the empty string. Setting the attribute to the empty string indicates that the primary language is unknown. [BCP47]
The lang
attribute in the XML namespace is defined in XML. [XML]
If these attributes are omitted from an element, then the language of this element is the same as the language of its parent element, if any.
The lang
attribute in no namespace may be used on any HTML element.
The lang
attribute in the XML namespace may be used on HTML elements in XML documents, as well as elements in other namespaces if the relevant specifications allow it (in particular, MathML and SVG allow lang
attributes in the XML namespace to be specified on their elements). If both the lang
attribute in no namespace and the lang
attribute in the XML namespace are specified on the same element, they must have exactly the same value when compared in an ASCII case-insensitive manner.
Authors must not use the lang
attribute in the XML namespace on HTML elements in HTML documents. To ease migration to and from XHTML, authors may specify an attribute in no namespace with no prefix and with the literal localname "xml:lang
" on HTML elements in HTML documents, but such attributes must only be specified if a lang
attribute in no namespace is also specified, and both attributes must have the same value when compared in an ASCII case-insensitive manner.
The attribute in no namespace with no prefix and with the literal localname "xml:lang
" has no effect on language processing.
The lang
IDL attribute must reflect the lang
content attribute in no namespace.
xml:base
attribute (XML only)The xml:base
attribute is defined in XML Base. [XMLBASE]
The xml:base
attribute may be used on elements of XML documents. Authors must not use the xml:base
attribute in HTML documents.
dir
attributeThe dir
attribute specifies the element's text directionality. The attribute is an enumerated attribute with the following keywords and states:
ltr
keyword, which maps to the ltr stateIndicates that the contents of the element are explicitly directionally embedded left-to-right text.
rtl
keyword, which maps to the rtl stateIndicates that the contents of the element are explicitly directionally embedded right-to-left text.
auto
keyword, which maps to the auto stateIndicates that the contents of the element are explicitly embedded text, but that the direction is to be determined programmatically using the contents of the element (as described below).
The heuristic used by this state is very crude (it just looks at the first character with a strong directionality, in a manner analogous to the Paragraph Level determination in the bidirectional algorithm). Authors are urged to only use this value as a last resort when the direction of the text is truly unknown and no better server-side heuristic can be applied.
For textarea
and pre
elements, the heuristic is applied on a per-paragraph level.
The attribute has no invalid value default and no missing value default.
The directionality of an element is either 'ltr' or 'rtl', and is determined as per the first appropriate set of steps from the following list:
dir
attribute is in the ltr stateThe directionality of the element is 'ltr'.
dir
attribute is in the rtl stateThe directionality of the element is 'rtl'.
dir
attribute is in the auto statebdi
element and the dir
attribute is not in a defined state (i.e. it is not present or has an invalid value)Find the first character in tree order that matches the following criteria:
The character is from a text node that is a descendant of the element whose directionality is being determined.
The character is of bidirectional character type L, AL, or R. [BIDI]
The character is not in a text node that has an ancestor element that is a descendant of the element whose directionality is being determined and that is either:
If such a character is found and it is of bidirectional character type AL or R, the directionality of the element is 'rtl'.
Otherwise, the directionality of the element is 'ltr'.
dir
attribute is not in a defined state (i.e. it is not present or has an invalid value)The directionality of the element is 'ltr'.
dir
attribute is not in a defined state (i.e. it is not present or has an invalid value)The directionality of the element is the same as the element's parent element's directionality.
The effect of this attribute is primarily on the presentation layer. For example, the rendering section in this specification defines a mapping from this attribute to the CSS 'direction' and 'unicode-bidi' properties, and CSS defines rendering in terms of those properties.
dir
[ = value ]Returns the html
element's dir
attribute's value, if any.
Can be set, to either "ltr
", "rtl
", or "auto
" to replace the html
element's dir
attribute's value.
If there is no html
element, returns the empty string and ignores new values.
The dir
IDL attribute on an element must reflect the dir
content attribute of that element, limited to only known values.
The dir
IDL attribute on HTMLDocument
objects must reflect the dir
content attribute of the html
element, if any, limited to only known values. If there is no such element, then the attribute must return the empty string and do nothing on setting.
Authors are strongly encouraged to use the dir
attribute to indicate text direction rather than using CSS, since that way their documents will continue to render correctly even in the absence of CSS (e.g. as interpreted by search engines).
This markup fragment is of an IM conversation.
<p dir=auto class="u1"><b><bdi>Student</bdi>:</b> How do you write "What's your name?" in Arabic?</p> <p dir=auto class="u2"><b><bdi>Teacher</bdi>:</b> ما اسمك؟</p> <p dir=auto class="u1"><b><bdi>Student</bdi>:</b> Thanks.</p> <p dir=auto class="u2"><b><bdi>Teacher</bdi>:</b> That's written "شكرًا".</p> <p dir=auto class="u2"><b><bdi>Teacher</bdi>:</b> Do you know how to write "Please"?</p> <p dir=auto class="u1"><b><bdi>Student</bdi>:</b> "من فضلك", right?</p>
Given a suitable style sheet and the default alignment styles for the p
element, namely to align the text to the start edge of the paragraph, the resulting rendering could be as follows:
As noted earlier, the auto
value is not a panacea. The final paragraph in this example is misinterpreted as being right-to-left text, since it begins with an Arabic character, which causes the "right?" to be to the left of the Arabic text.
class
attributeEvery HTML element may have a class
attribute specified.
The attribute, if specified, must have a value that is a set of space-separated tokens representing the various classes that the element belongs to.
Assigning classes to an element affects class matching in selectors in CSS, the getElementsByClassName()
method in the DOM, and other such features.
There are no additional restrictions on the tokens authors can use in the class
attribute, but authors are encouraged to use values that describe the nature of the content, rather than values that describe the desired presentation of the content.
The className
and classList
IDL attributes must both reflect the class
content attribute.
style
attributeAll HTML elements may have the style
content attribute set. This is a CSS styling attribute as defined by the CSS Styling Attribute Syntax specification. [CSSATTR]
Documents that use style
attributes on any of their elements must still be comprehensible and usable if those attributes were removed.
In particular, using the style
attribute to hide and show content, or to convey meaning that is otherwise not included in the document, is non-conforming. (To hide and show content, use the attribute.)
style
Returns a CSSStyleDeclaration
object for the element's style
attribute.
In the following example, the words that refer to colors are marked up using the span
element and the style
attribute to make those words show up in the relevant colors in visual media.
<p>My sweat suit is <span style="color: green; background: transparent">green</span> and my eyes are <span style="color: blue; background: transparent">blue</span>.</p>
data-*
attributesA custom data attribute is an attribute in no namespace whose name starts with the string "data-
", has at least one character after the hyphen, is XML-compatible, and contains no characters in the range U+0041 to U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z).
All attributes on HTML elements in HTML documents get ASCII-lowercased automatically, so the restriction on ASCII uppercase letters doesn't affect such documents.
Custom data attributes are intended to store custom data private to the page or application, for which there are no more appropriate attributes or elements.
These attributes are not intended for use by software that is independent of the site that uses the attributes.
For instance, a site about music could annotate list items representing tracks in an album with custom data attributes containing the length of each track. This information could then be used by the site itself to allow the user to sort the list by track length, or to filter the list for tracks of certain lengths.
<ol> <li data-length="2m11s">Beyond The Sea</li> ... </ol>
It would be inappropriate, however, for the user to use generic software not associated with that music site to search for tracks of a certain length by looking at this data.
This is because these attributes are intended for use by the site's own scripts, and are not a generic extension mechanism for publicly-usable metadata.
Every HTML element may have any number of custom data attributes specified, with any value.
dataset
Returns a DOMStringMap
object for the element's data-*
attributes.
Hyphenated names become camel-cased. For example, data-foo-bar=""
becomes element.dataset.fooBar
.
If a Web page wanted an element to represent a space ship, e.g. as part of a game, it would have to use the class
attribute along with data-*
attributes:
<div class="spaceship" data-ship-id="92432" data-weapons="laser 2" data-shields="50%" data-x="30" data-y="10" data-z="90"> <button class="fire" onclick="spaceships[this.parentNode.dataset.shipId].fire()"> Fire </button> </div>
Notice how the hyphenated attribute name becomes camel-cased in the API.
Authors should carefully design such extensions so that when the attributes are ignored and any associated CSS dropped, the page is still usable.
JavaScript libraries may use the custom data attributes, as they are considered to be part of the page on which they are used. Authors of libraries that are reused by many authors are encouraged to include their name in the attribute names, to reduce the risk of clashes. Where it makes sense, library authors are also encouraged to make the exact name used in the attribute names customizable, so that libraries whose authors unknowingly picked the same name can be used on the same page, and so that multiple versions of a particular library can be used on the same page even when those versions are not mutually compatible.
For example, a library called "DoQuery" could use attribute names like data-doquery-range
, and a library called "jJo" could use attributes names like data-jjo-range
. The jJo library could also provide an API to set which prefix to use (e.g. J.setDataPrefix('j2')
, making the attributes have names like data-j2-range
).
Each element in this specification has a definition that includes the following information:
A list of categories to which the element belongs. These are used when defining the content models for each element.
A non-normative description of where the element can be used. This information is redundant with the content models of elements that allow this one as a child, and is provided only as a convenience.
For simplicity, only the most specific expectations are listed. For example, an element that is both flow content and phrasing content can be used anywhere that either flow content or phrasing content is expected, but since anywhere that flow content is expected, phrasing content is also expected (since all phrasing content is flow content), only "where phrasing content is expected" will be listed.
A normative description of what content must be included as children and descendants of the element.
A normative list of attributes that may be specified on the element (except where otherwise disallowed).
A normative definition of a DOM interface that such elements must implement.
This is then followed by a description of what the element represents, along with any additional normative conformance criteria that may apply to authors. Examples are sometimes also included.
Except where otherwise specified, attributes on HTML elements may have any string value, including the empty string. Except where explicitly stated, there is no restriction on what text can be specified in such attributes.
Each element defined in this specification has a content model: a description of the element's expected contents. An HTML element must have contents that match the requirements described in the element's content model.
As noted in the conformance and terminology sections, for the purposes of determining if an element matches its content model or not, CDATASection
nodes in the DOM are treated as equivalent to Text
nodes, and entity reference nodes are treated as if they were expanded in place.
The space characters are always allowed between elements. User agents represent these characters between elements in the source markup as text nodes in the DOM. Empty text nodes and text nodes consisting of just sequences of those characters are considered inter-element whitespace.
Inter-element whitespace, comment nodes, and processing instruction nodes must be ignored when establishing whether an element's contents match the element's content model or not, and must be ignored when following algorithms that define document and element semantics.
Thus, an element A is said to be preceded or followed by a second element B if A and B have the same parent node and there are no other element nodes or text nodes (other than inter-element whitespace) between them. Similarly, a node is the only child of an element if that element contains no other nodes other than inter-element whitespace, comment nodes, and processing instruction nodes.
Authors must not use HTML elements anywhere except where they are explicitly allowed, as defined for each element, or as explicitly required by other specifications. For XML compound documents, these contexts could be inside elements from other namespaces, if those elements are defined as providing the relevant contexts.
For example, the Atom specification defines a content
element. When its type
attribute has the value xhtml
, the Atom specification requires that it contain a single HTML div
element. Thus, a div
element is allowed in that context, even though this is not explicitly normatively stated by this specification. [ATOM]
In addition, HTML elements may be orphan nodes (i.e. without a parent node).
For example, creating a td
element and storing it in a global variable in a script is conforming, even though td
elements are otherwise only supposed to be used inside tr
elements.
var data = { name: "Banana", cell: document.createElement('td'), };
Each element in HTML falls into zero or more categories that group elements with similar characteristics together. The following broad categories are used in this specification:
Some elements also fall into other categories, which are defined in other parts of this specification.
These categories are related as follows:
In addition, certain elements are categorized as form-associated elements and further subcategorized to define their role in various form-related processing models.
Some elements have unique requirements and do not fit into any particular category.
Metadata content is content that sets up the presentation or behavior of the rest of the content, or that sets up the relationship of the document with other documents, or that conveys other "out of band" information.
Elements from other namespaces whose semantics are primarily metadata-related (e.g. RDF) are also metadata content.
Thus, in the XML serialization, one can use RDF, like this:
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:r="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <head> <title>Hedral's Home Page</title> <r:RDF> <Person xmlns="http://www.w3.org/2000/10/swap/pim/contact#" r:about="http://hedral.example.com/#"> <fullName>Cat Hedral</fullName> <mailbox r:resource="mailto:hedral@damowmow.com"/> <personalTitle>Sir</personalTitle> </Person> </r:RDF> </head> <body> <h1>My home page</h1> <p>I like playing with string, I guess. Sister says squirrels are fun too so sometimes I follow her to play with them.</p> </body> </html>
This isn't possible in the HTML serialization, however.
Most elements that are used in the body of documents and applications are categorized as flow content.
a
abbr
address
area
(if it is a descendant of a map
element)article
aside
audio
b
bdi
bdo
blockquote
br
button
canvas
cite
code
command
datalist
del
details
dfn
div
dl
em
embed
fieldset
figure
footer
form
h1
h2
h3
h4
h5
h6
header
hgroup
hr
i
iframe
img
input
ins
kbd
keygen
label
map
mark
math
menu
meter
nav
noscript
object
ol
output
p
pre
progress
q
ruby
s
samp
script
section
select
small
span
strong
style
(if the scoped
attribute is present)sub
sup
svg
table
textarea
time
u
ul
var
video
wbr
As a general rule, elements whose content model allows any flow content should have either at least one descendant text node that is not inter-element whitespace, or at least one descendant element node that is embedded content. For the purposes of this requirement, del
elements and their descendants must not be counted as contributing to the ancestors of the del
element.
This requirement is not a hard requirement, however, as there are many cases where an element can be empty legitimately, for example when it is used as a placeholder which will later be filled in by a script, or when the element is part of a template and would on most pages be filled in but on some pages is not relevant.
Sectioning content is content that defines the scope of headings and footers.
Each sectioning content element potentially has a heading and an outline. See the section on headings and sections for further details.
There are also certain elements that are sectioning roots. These are distinct from sectioning content, but they can also have an outline.
Heading content defines the header of a section (whether explicitly marked up using sectioning content elements, or implied by the heading content itself).
Phrasing content is the text of the document, as well as elements that mark up that text at the intra-paragraph level. Runs of phrasing content form paragraphs.
a
(if it contains only phrasing content)abbr
area
(if it is a descendant of a map
element)audio
b
bdi
bdo
br
button
canvas
cite
code
command
datalist
del
(if it contains only phrasing content)dfn
em
embed
i
iframe
img
input
ins
(if it contains only phrasing content)kbd
keygen
label
map
(if it contains only phrasing content)mark
math
meter
noscript
object
output
progress
q
ruby
s
samp
script
select
small
span
strong
sub
sup
svg
textarea
time
u
var
video
wbr
As a general rule, elements whose content model allows any phrasing content should have either at least one descendant text node that is not inter-element whitespace, or at least one descendant element node that is embedded content. For the purposes of this requirement, nodes that are descendants of del
elements must not be counted as contributing to the ancestors of the del
element.
Most elements that are categorized as phrasing content can only contain elements that are themselves categorized as phrasing content, not any flow content.
Text, in the context of content models, means text nodes. Text is sometimes used as a content model on its own, but is also phrasing content, and can be inter-element whitespace (if the text nodes are empty or contain just space characters).
Embedded content is content that imports another resource into the document, or content from another vocabulary that is inserted into the document.
Elements that are from namespaces other than the HTML namespace and that convey content but not metadata, are embedded content for the purposes of the content models defined in this specification. (For example, MathML, or SVG.)
Some embedded content elements can have fallback content: content that is to be used when the external resource cannot be used (e.g. because it is of an unsupported format). The element definitions state what the fallback is, if any.
Interactive content is content that is specifically intended for user interaction.
a
audio
(if the controls
attribute is present)button
details
embed
iframe
img
(if the usemap
attribute is present)input
(if the type
attribute is not in the state)keygen
label
menu
(if the type
attribute is in the toolbar state)object
(if the usemap
attribute is present)select
textarea
video
(if the controls
attribute is present)Certain elements in HTML have an activation behavior, which means that the user can activate them. This triggers a sequence of events dependent on the activation mechanism, and normally culminating in a click
event.
Some elements are described as transparent; they have "transparent" in the description of their content model. The content model of a transparent element is derived from the content model of its parent element: the elements required in the part of the content model that is "transparent" are the same elements as required in the part of the content model of the parent of the transparent element in which the transparent element finds itself.
For instance, an ins
element inside a ruby
element cannot contain an rt
element, because the part of the ruby
element's content model that allows ins
elements is the part that allows phrasing content, and the rt
element is not phrasing content.
In some cases, where transparent elements are nested in each other, the process has to be applied iteratively.
Consider the following markup fragment:
<p><object><param><ins><map><a href="/">Apples</a></map></ins></object></p>
To check whether "Apples" is allowed inside the a
element, the content models are examined. The a
element's content model is transparent, as is the map
element's, as is the ins
element's, as is the part of the object
element's in which the ins
element is found. The object
element is found in the p
element, whose content model is phrasing content. Thus, "Apples" is allowed, as text is phrasing content.
When a transparent element has no parent, then the part of its content model that is "transparent" must instead be treated as accepting any flow content.
The term paragraph as defined in this section is distinct from (though related to) the p
element defined later. The paragraph concept defined here is used to describe how to interpret documents.
A paragraph is typically a run of phrasing content that forms a block of text with one or more sentences that discuss a particular topic, as in typography, but can also be used for more general thematic grouping. For instance, an address is also a paragraph, as is a part of a form, a byline, or a stanza in a poem.
In the following example, there are two paragraphs in a section. There is also a heading, which contains phrasing content that is not a paragraph. Note how the comments and inter-element whitespace do not form paragraphs.
<section> <h1>Example of paragraphs</h1> This is the <em>first</em> paragraph in this example. <p>This is the second.</p> <!-- This is not a paragraph. --> </section>
Paragraphs in flow content are defined relative to what the document looks like without the a
, ins
, del
, and map
elements complicating matters, since those elements, with their hybrid content models, can straddle paragraph boundaries, as shown in the first two examples below.
Generally, having elements straddle paragraph boundaries is best avoided. Maintaining such markup can be difficult.
The following example takes the markup from the earlier example and puts ins
and del
elements around some of the markup to show that the text was changed (though in this case, the changes admittedly don't make much sense). Notice how this example has exactly the same paragraphs as the previous one, despite the ins
and del
elements — the ins
element straddles the heading and the first paragraph, and the del
element straddles the boundary between the two paragraphs.
<section> <ins><h1>Example of paragraphs</h1> This is the <em>first</em> paragraph in</ins> this example<del>. <p>This is the second.</p></del> <!-- This is not a paragraph. --> </section>
A paragraph is also formed explicitly by p
elements.
The p
element can be used to wrap individual paragraphs when there would otherwise not be any content other than phrasing content to separate the paragraphs from each other.
In the following example, the link spans half of the first paragraph, all of the heading separating the two paragraphs, and half of the second paragraph. It straddles the paragraphs and the heading.
<aside> Welcome! <a href="about.html"> This is home of... <h1>The Falcons!</h1> The Lockheed Martin multirole jet fighter aircraft! </a> This page discusses the F-16 Fighting Falcon's innermost secrets. </aside>
Here is another way of marking this up, this time showing the paragraphs explicitly, and splitting the one link element into three:
<aside> <p>Welcome! <a href="about.html">This is home of...</a></p> <h1><a href="about.html">The Falcons!</a></h1> <p><a href="about.html">The Lockheed Martin multirole jet fighter aircraft!</a> This page discusses the F-16 Fighting Falcon's innermost secrets.</p> </aside>
It is possible for paragraphs to overlap when using certain elements that define fallback content. For example, in the following section:
<section> <h1>My Cats</h1> You can play with my cat simulator. <object data="cats.sim"> To see the cat simulator, use one of the following links: <ul> <li><a href="cats.sim">Download simulator file</a> <li><a href="http://sims.example.com/watch?v=LYds5xY4INU">Use online simulator</a> </ul> Alternatively, upgrade to the Mellblom Browser. </object> I'm quite proud of it. </section>
There are five paragraphs:
object
element.The first paragraph is overlapped by the other four. A user agent that supports the "cats.sim" resource will only show the first one, but a user agent that shows the fallback will confusingly show the first sentence of the first paragraph as if it was in the same paragraph as the second one, and will show the last paragraph as if it was at the start of the second sentence of the first paragraph.
To avoid this confusion, explicit p
elements can be used.
Text content in HTML elements with child text nodes, and text in attributes of HTML elements that allow free-form text, may contain characters in the range U+202A to U+202E (the bidirectional-algorithm formatting characters). However, the use of these characters is restricted so that any embedding or overrides generated by these characters do not start and end with different parent elements, and so that all such embeddings and overrides are explicitly terminated by a U+202C POP DIRECTIONAL FORMATTING character. This helps reduce incidences of text being reused in a manner that has unforeseen effects on the bidirectional algorithm.
The aforementioned restrictions are defined by specifying that certain parts of documents form bidirectional-algorithm formatting character ranges, and then imposing a requirement on such ranges.
The string resulting from the concatenation of the data of all of an HTML element's text nodes, if any, is a bidirectional-algorithm formatting character range.
The value of a namespace-less attribute of an HTML element is a bidirectional-algorithm formatting character range.
Any strings that, as described above, are bidirectional-algorithm formatting character ranges must match the string
production in the following ABNF, the character set for which is Unicode. [ABNF]
string = *( plaintext ( embedding / override ) ) plaintext embedding = ( lre / rle ) string pdf override = ( lro / rlo ) string pdf lre = %x202A ; U+202A LEFT-TO-RIGHT EMBEDDING rle = %x202B ; U+202B RIGHT-TO-LEFT EMBEDDING lro = %x202D ; U+202D LEFT-TO-RIGHT OVERRIDE rlo = %x202E ; U+202E RIGHT-TO-LEFT OVERRIDE pdf = %x202C ; U+202C POP DIRECTIONAL FORMATTING plaintext = *( %x0000-2029 / %x202F-10FFFF ) ; any string with no bidirectional-algorithm formatting characters
For convenience, where possible authors will likely prefer to use the dir
attribute, the bdo
element, and the bdi
element, rather than maintaining the bidirectional-algorithm formatting characters manually.
Authors may use the ARIA role
and aria-*
attributes on HTML elements, in accordance with the requirements described in the ARIA specifications, except where these conflict with the strong native semantics described below. These exceptions are intended to prevent authors from making assistive technology products report nonsensical states that do not represent the actual state of the document. [ARIA]
The following table defines the strong native semantics and corresponding default implicit ARIA semantics that apply to HTML elements. Each language feature (element or attribute) in a cell in the first column implies the ARIA semantics (role, states, and/or properties) given in the cell in the second column of the same row.
Language feature | Strong native semantics and default implied ARIA semantics |
---|---|
area element that creates a hyperlink |
link role |
base element |
No role |
datalist element |
listbox role, with the aria-multiselectable property set to "false" |
details element |
aria-expanded state set to "true" if the element's open attribute is present, and set to "false" otherwise |
head element |
No role |
hgroup element |
heading role, with the aria-level property set to the element's outline depth |
hr element |
separator role |
html element |
No role |
img element whose alt attribute's value is empty |
presentation role |
input element with a type attribute in the Checkbox state |
aria-checked state set to "mixed" if the element's indeterminate IDL attribute is true, or "true" if the element's checkedness is true, or "false" otherwise |
input element with a type attribute in the Color state |
No role |
input element with a type attribute in the Date state |
No role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Date and Time state |
No role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Local Date and Time state |
No role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the E-mail state with no suggestions source element |
textbox role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the File Upload state |
No role |
input element with a type attribute in the state |
No role |
input element with a type attribute in the Month state |
No role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Number state |
spinbutton role, with the aria-readonly state set to "true" if the element has a readonly attribute, the aria-valuemax property set to the element's maximum, the aria-valuemin property set to the element's minimum, and, if the result of applying the rules for parsing floating point number values to the element's value is a number, with the aria-valuenow property set to that number |
input element with a type attribute in the Password state |
textbox role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Radio Button state |
aria-checked state set to "true" if the element's checkedness is true, or "false" otherwise |
input element with a type attribute in the Range state |
slider role, with the aria-valuemax property set to the element's maximum, the aria-valuemin property set to the element's minimum, and the aria-valuenow property set to the result of applying the rules for parsing floating point number values to the element's value, if that results in a number, or the default value otherwise |
input element with a type attribute in the Reset Button state |
button role |
input element with a type attribute in the Search state with no suggestions source element |
textbox role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Submit Button state |
button role |
input element with a type attribute in the Telephone state with no suggestions source element |
textbox role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Text state with no suggestions source element |
textbox role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Text, Search, Telephone, URL, or E-mail states with a suggestions source element |
combobox role, with the aria-owns property set to the same value as the list attribute, and the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Time state |
No role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the URL state with no suggestions source element |
textbox role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element with a type attribute in the Week state |
No role, with the aria-readonly state set to "true" if the element has a readonly attribute |
input element that is required |
The aria-required state set to "true" |
keygen element |
No role |
label element |
No role |
link element that creates a hyperlink |
link role |
menu element with a type attribute in the context menu state |
No role |
menu element with a type attribute in the list state |
menu role |
menu element with a type attribute in the toolbar state |
toolbar role |
meta element |
No role |
meter element |
No role |
nav element |
navigation role |
noscript element |
No role |
optgroup element |
No role |
option element that is in a list of options or that represents a suggestion in a datalist element |
option role, with the aria-selected state set to "true" if the element's selectedness is true, or "false" otherwise. |
param element |
No role |
progress element |
progressbar role, with, if the progress bar is determinate, the aria-valuemax property set to the maximum value of the progress bar, the aria-valuemin property set to zero, and the aria-valuenow property set to the current value of the progress bar |
script element |
No role |
select element with a multiple attribute |
listbox role, with the aria-multiselectable property set to "true" |
select element with no multiple attribute |
listbox role, with the aria-multiselectable property set to "false" |
select element with a required attribute |
The aria-required state set to "true" |
source element |
No role |
style element |
No role |
summary element |
No role |
textarea element |
textbox role, with the aria-multiline property set to "true", and the aria-readonly state set to "true" if the element has a readonly attribute |
textarea element with a required attribute |
The aria-required state set to "true" |
title element |
No role |
An element that defines a command, whose Type facet is "checkbox", and that is a descendant of a menu element whose type attribute in the list state |
menuitemcheckbox role, with the aria-checked state set to "true" if the command's Checked State facet is true, and "false" otherwise |
An element that defines a command, whose Type facet is "command", and that is a descendant of a menu element whose type attribute in the list state |
menuitem role |
An element that defines a command, whose Type facet is "radio", and that is a descendant of a menu element whose type attribute in the list state |
menuitemradio role, with the aria-checked state set to "true" if the command's Checked State facet is true, and "false" otherwise |
Element that is disabled | The aria-disabled state set to "true" |
Element with a attribute |
The aria-hidden state set to "true" |
Element that is a candidate for constraint validation but that does not satisfy its constraints | The aria-invalid state set to "true" |
Some HTML elements have native semantics that can be overridden. The following table lists these elements and their default implicit ARIA semantics, along with the restrictions that apply to those elements. Each language feature (element or attribute) in a cell in the first column implies, unless otherwise overridden, the ARIA semantic (role, state, or property) given in the cell in the second column of the same row, but this semantic may be overridden under the conditions listed in the cell in the third column of that row. In addition, any element may be given the presentation
role, regardless of the restrictions below.
Language feature | Default implied ARIA semantic | Restrictions |
---|---|---|
a element that creates a hyperlink |
link role |
Role must be either link , button , checkbox , menuitem , menuitemcheckbox , menuitemradio , tab , or treeitem |
address element |
No role | If specified, role must be contentinfo |
article element |
article role |
Role must be either article , document , application , or main |
aside element |
note role |
Role must be either note , complementary , or search |
audio element |
No role | If specified, role must be application |
button element |
button role |
Role must be either button , link , menuitem , menuitemcheckbox , menuitemradio , radio |
details element |
group role |
Role must be a role that supports aria-expanded |
embed element |
No role | If specified, role must be either application , document , or img |
footer element |
No role | If specified, role must be contentinfo |
h1 element that does not have an hgroup ancestor |
heading role, with the aria-level property set to the element's outline depth |
Role must be either link , menuitem , menuitemcheckbox , menuitemradio , tab , or treeitem |
h2 element that does not have an hgroup ancestor |
heading role, with the aria-level property set to the element's outline depth |
Role must be either link , menuitem , menuitemcheckbox , menuitemradio , tab , or treeitem |
h3 element that does not have an hgroup ancestor |
heading role, with the aria-level property set to the element's outline depth |
Role must be either link , menuitem , menuitemcheckbox , menuitemradio , tab , or treeitem |
h4 element that does not have an hgroup ancestor |
heading role, with the aria-level property set to the element's outline depth |
Role must be either link , menuitem , menuitemcheckbox , menuitemradio , tab , or treeitem |
h5 element that does not have an hgroup ancestor |
heading role, with the aria-level property set to the element's outline depth |
Role must be either link , menuitem , menuitemcheckbox , menuitemradio , tab , or treeitem |
h6 element that does not have an hgroup ancestor |
heading role, with the aria-level property set to the element's outline depth |
Role must be either link , menuitem , menuitemcheckbox , menuitemradio , tab , or treeitem |
header element |
No role | If specified, role must be banner |
iframe element |
No role | If specified, role must be either application , document , or img |
img element whose alt attribute's value is absent |
img role |
No restrictions |
img element whose alt attribute's value is present and not empty |
img role |
No restrictions |
input element with a type attribute in the Button state |
button role |
Role must be either button , link , menuitem , menuitemcheckbox , menuitemradio , radio |
input element with a type attribute in the Checkbox state |
checkbox role |
Role must be either checkbox or menuitemcheckbox |
input element with a type attribute in the Image Button state |
button role |
Role must be either button , link , menuitem , menuitemcheckbox , menuitemradio , radio |
input element with a type attribute in the Radio Button state |
radio role |
Role must be either radio or menuitemradio |
li element whose parent is an ol or ul element |
listitem role |
Role must be either listitem , menuitemcheckbox , menuitemradio , option , tab , or treeitem |
object element |
No role | If specified, role must be either application , document , or img |
ol element |
list role |
Role must be either directory , list , listbox , menu , menubar , tablist , toolbar , tree |
output element |
status role |
No restrictions |
section element |
region role |
Role must be either alert , alertdialog , application , contentinfo , dialog , document , log , main , marquee , region , search , or status |
ul element |
list role |
Role must be either directory , list , listbox , menu , menubar , tablist , toolbar , tree |
video element |
No role | If specified, role must be application |
The body element | document role |
Role must be either document or application |
The entry "no role", when used as a strong native semantic, means that no role other than presentation
can be used. When used as a default implied ARIA semantic, it means the user agent has no default mapping to ARIA roles. (However, it probably will have its own mappings to the accessibility layer.)
These features can be used to make accessibility tools render content to their users in more useful ways. For example, ASCII art, which is really an image, appears to be text, and in the absence of appropriate annotations would end up being rendered by screen readers as a very painful reading of lots of punctuation. Using the features described in this section, one can instead make the ATs skip the ASCII art and just read the caption:
<figure role="img" aria-labelledby="fish-caption"> <pre> o .'`/ ' / ( O .-'` ` `'-._ .') _/ (o) '. .' / ) ))) >< < `\ |_\ _.' '. \ '-._ _ .-' '.) jgs `\__\ </pre> <figcaption id="fish-caption"> Joan G. Stark, "<cite>fish</cite>". October 1997. ASCII on electrons. 28×8. </figcaption> </figure>
For HTML documents, and for HTML elements in HTML documents, certain APIs defined in DOM Core become case-insensitive or case-changing, as sometimes defined in DOM Core, and as summarized below. [DOMCORE]
This does not apply to XML documents or to elements that are not in the HTML namespace despite being in HTML documents.
Element.tagName
and Node.nodeName
These attributes return element names converted to ASCII uppercase, regardless of the case with which they were created.
Document.createElement()
The canonical form of HTML markup is all-lowercase; thus, this method will lowercase the argument before creating the requisite element. .
This doesn't apply to Document.createElementNS()
. Thus, it is possible, by passing this last method a tag name in the wrong case, to create an element that appears to have the same tag name as that of an element defined in this specification when its tagName
attribute is examined, but that doesn't support the corresponding interfaces. The "real" element name (unaffected by case conversions) can be obtained from the localName
attribute.
Element.setAttribute()
Element.setAttributeNode()
Attribute names are converted to ASCII lowercase.
This doesn't apply to Element.setAttributeNS()
and Element.setAttributeNodeNS()
.
Element.getAttribute()
Element.getAttributeNode()
Attribute names are converted to ASCII lowercase.
This doesn't apply to Element.getAttributeNS()
and Element.getAttributeNodeNS()
.
Document.getElementsByTagName()
Element.getElementsByTagName()
HTML elements match by lower-casing the argument before comparison, elements from other namespaces are treated as in XML (case-sensitively).
Thus, in an HTML document with nodes in multiple namespaces, these methods will effectively be both case-sensitive and case-insensitive at the same time.
APIs for dynamically inserting markup into the document interact with the parser, and thus their behavior varies depending on whether they are used with HTML documents (and the HTML parser) or XHTML in XML documents (and the XML parser).
The open()
method comes in several variants with different numbers of arguments.
open
( [ type [, replace ] ] )Causes the Document
to be replaced in-place, as if it was a new Document
object, but reusing the previous object, which is then returned.
If the type argument is omitted or has the value "text/html
", then the resulting Document
has an HTML parser associated with it, which can be given data to parse using document.write()
. Otherwise, all content passed to document.write()
will be parsed as plain text.
If the replace argument is present and has the value "replace
", the existing entries in the session history for the Document
object are removed.
The method has no effect if the Document
is still being parsed.
Throws an INVALID_STATE_ERR
exception if the Document
is an XML document.
open
( url, name, features [, replace ] )Works like the window.open()
method.
close
()Closes the input stream that was opened by the document.open()
method.
Throws an INVALID_STATE_ERR
exception if the Document
is an XML document.
document.write()
write
(text...)In general, adds the given string(s) to the Document
's input stream.
This method has very idiosyncratic behavior. In some cases, this method can affect the state of the HTML parser while the parser is running, resulting in a DOM that does not correspond to the source of the document. In other cases, the call can clear the current page first, as if document.open()
had been called. In yet more cases, the method is simply ignored, or throws an exception. To make matters worse, the exact behavior of this method can in some cases be dependent on network latency, which can lead to failures that are very hard to debug. For all these reasons, use of this method is strongly discouraged.
This method throws an INVALID_STATE_ERR
exception when invoked on XML documents.
document.writeln()
writeln
(text...)Adds the given string(s) to the Document
's input stream, followed by a newline character. If necessary, calls the open()
method implicitly first.
This method throws an INVALID_STATE_ERR
exception when invoked on XML documents.
innerHTML
The innerHTML
IDL attribute represents the markup of the node's contents.
innerHTML
[ = value ]Returns a fragment of HTML or XML that represents the Document
.
Can be set, to replace the Document
's contents with the result of parsing the given string.
In the case of XML documents, will throw an INVALID_STATE_ERR
if the Document
cannot be serialized to XML, and a SYNTAX_ERR
if the given string is not well-formed.
innerHTML
[ = value ]Returns a fragment of HTML or XML that represents the element's contents.
Can be set, to replace the contents of the element with nodes parsed from the given string.
In the case of XML documents, will throw an INVALID_STATE_ERR
if the element cannot be serialized to XML, and a SYNTAX_ERR
if the given string is not well-formed.
outerHTML
The outerHTML
IDL attribute represents the markup of the element and its contents.
outerHTML
[ = value ]Returns a fragment of HTML or XML that represents the element and its contents.
Can be set, to replace the element with nodes parsed from the given string.
In the case of XML documents, will throw an INVALID_STATE_ERR
if the element cannot be serialized to XML, and a SYNTAX_ERR
if the given string is not well-formed.
Throws a NO_MODIFICATION_ALLOWED_ERR
exception if the parent of the element is the Document
node.
insertAdjacentHTML()
insertAdjacentHTML
(position, text)Parses the given string text as HTML or XML and inserts the resulting nodes into the tree in the position given by the position argument, as follows:
Throws a SYNTAX_ERR
exception if the arguments have invalid values (e.g., in the case of XML documents, if the given string is not well-formed).
Throws a NO_MODIFICATION_ALLOWED_ERR
exception if the given position isn't possible (e.g. inserting elements after the root element of a Document
).
The html element.
html
elementhead
element followed by a body
element.manifest
interface HTMLHtmlElement : HTMLElement {};
The html
element represents the root of an HTML document.
The manifest
attribute gives the address of the document's application cache manifest, if there is one. If the attribute is present, the attribute's value must be a valid non-empty URL potentially surrounded by spaces.
The manifest
attribute only has an effect during the early stages of document load. Changing the attribute dynamically thus has no effect (and thus, no DOM API is provided for this attribute).
For the purposes of application cache selection, later base
elements cannot affect the resolving of relative URLs in manifest
attributes, as the attributes are processed before those elements are seen.
The window.applicationCache
IDL attribute provides scripted access to the offline application cache mechanism.
The html
element in the following example declares that the document's language is English.
<!DOCTYPE html> <html lang="en"> <head> <title>Swapping Songs</title> </head> <body> <h1>Swapping Songs</h1> <p>Tonight I swapped some of the songs I wrote with some friends, who gave me some of the songs they wrote. I love sharing my music.</p> </body> </html>
head
elementhtml
element.iframe
srcdoc
document or if title information is available from a higher-level protocol: Zero or more elements of metadata content.title
element.interface HTMLHeadElement : HTMLElement {};
The head
element represents a collection of metadata for the Document
.
The collection of metadata in a head
element can be large or small. Here is an example of a very short one:
<!doctype html> <html> <head> <title>A document with a short head</title> </head> <body> ...
Here is an example of a longer one:
<!DOCTYPE HTML> <HTML> <HEAD> <META CHARSET="UTF-8"> <BASE HREF="http://www.example.com/"> <TITLE>An application with a long head</TITLE> <LINK REL="STYLESHEET" HREF="default.css"> <LINK REL="STYLESHEET ALTERNATE" HREF="big.css" TITLE="Big Text"> <SCRIPT SRC="support.js"></SCRIPT> <META NAME="APPLICATION-NAME" CONTENT="Long headed application"> </HEAD> <BODY> ...
The title
element is a required child in most situations, but when a higher-level protocol provides title information, e.g. in the Subject line of an e-mail when HTML is used as an e-mail authoring format, the title
element can be omitted.
title
elementhead
element containing no other title
elements.interface HTMLTitleElement : HTMLElement { attribute DOMString text; };
The title
element represents the document's title or name. Authors should use titles that identify their documents even when they are used out of context, for example in a user's history or bookmarks, or in search results. The document's title is often different from its first heading, since the first heading does not have to stand alone when taken out of context.
There must be no more than one title
element per document.
text
[ = value ]Returns the contents of the element, ignoring child nodes that aren't text nodes.
Can be set, to replace the element's children with the given value.
Here are some examples of appropriate titles, contrasted with the top-level headings that might be used on those same pages.
<title>Introduction to The Mating Rituals of Bees</title> ... <h1>Introduction</h1> <p>This companion guide to the highly successful <cite>Introduction to Medieval Bee-Keeping</cite> book is...
The next page might be a part of the same site. Note how the title describes the subject matter unambiguously, while the first heading assumes the reader knows what the context is and therefore won't wonder if the dances are Salsa or Waltz:
<title>Dances used during bee mating rituals</title> ... <h1>The Dances</h1>
The string to use as the document's title is given by the document.title
IDL attribute.
base
elementhead
element containing no other base
elements.href
target
interface HTMLBaseElement : HTMLElement { attribute DOMString href; attribute DOMString target; };
The base
element allows authors to specify the document base URL for the purposes of resolving relative URLs, and the name of the default browsing context for the purposes of following hyperlinks. The element does not represent any content beyond this information.
There must be no more than one base
element per document.
A base
element must have either an href
attribute, a target
attribute, or both.
The href
content attribute, if specified, must contain a valid URL potentially surrounded by spaces.
A base
element, if it has an href
attribute, must come before any other elements in the tree that have attributes defined as taking URLs, except the html
element (its manifest
attribute isn't affected by base
elements).
The target
attribute, if specified, must contain a valid browsing context name or keyword, which specifies which browsing context is to be used as the default when hyperlinks and forms in the Document
cause navigation.
A base
element, if it has a target
attribute, must come before any elements in the tree that represent hyperlinks.
The href
IDL attribute, on getting, must return the page's document base URL, and on setting, it must set the href
content attribute to the given new value.
The target
IDL attribute must reflect the content attribute of the same name.
In this example, a base
element is used to set the document base URL:
<!DOCTYPE html> <html> <head> <title>This is an example for the <base> element</title> <base href="http://www.example.com/news/index.html"> </head> <body> <p>Visit the <a href="archives.html">archives</a>.</p> </body> </html>
The link in the above example would be a link to "http://www.example.com/news/archives.html
".
link
elementnoscript
element that is a child of a head
element.href
rel
media
hreflang
type
sizes
title
attribute has special semantics on this element.interface HTMLLinkElement : HTMLElement {
attribute boolean disabled;
attribute DOMString href;
attribute DOMString rel;
readonly attribute DOMTokenList relList;
attribute DOMString media;
attribute DOMString hreflang;
attribute DOMString type;
[PutForwards=value] readonly attribute DOMSettableTokenList sizes;
};
HTMLLinkElement implements LinkStyle;
The link
element allows authors to link their document to other resources.
The destination of the link(s) is given by the href
attribute, which must be present and must contain a valid non-empty URL potentially surrounded by spaces.
A link
element must have rel
attribute.
The types of link indicated (the relationships) are given by the value of the rel
attribute, which, if present, must have a value that is a set of space-separated tokens. The allowed keywords and their meanings are defined in a later section.
Two categories of links can be created using the link
element: Links to external resources and hyperlinks. The link types section defines whether a particular link type is an external resource or a hyperlink. One link
element can create multiple links (of which some might be external resource links and some might be hyperlinks); exactly which and how many links are created depends on the keywords given in the rel
attribute. User agents must process the links on a per-link basis, not a per-element basis.
Each link created for a link
element is handled separately. For instance, if there are two link
elements with rel="stylesheet"
, they each count as a separate external resource, and each is affected by its own attributes independently. Similarly, if a single link
element has a rel
attribute with the value next stylesheet
, it creates both a hyperlink (for the next
keyword) and an external resource link (for the stylesheet
keyword), and they are affected by other attributes (such as media
or title
) differently.
The exact behavior for links to external resources depends on the exact relationship, as defined for the relevant link type. Some of the attributes control whether or not the external resource is to be applied (as defined below).
Hyperlinks created with the link
element and its rel
attribute apply to the whole page. This contrasts with the rel
attribute of a
and area
elements, which indicates the type of a link whose context is given by the link's location within the document.
The media
attribute says which media the resource applies to. The value must be a valid media query.
The default, if the media
attribute is omitted, is "all
", meaning that by default links apply to all media.
The hreflang
attribute on the link
element has the same semantics as the hreflang
attribute on a
and area
elements.
The type
attribute gives the MIME type of the linked resource. It is purely advisory. The value must be a valid MIME type.
For external resource links, the type
attribute is used as a hint to user agents so that they can avoid fetching resources they do not support.
The title
attribute gives the title of the link. With one exception, it is purely advisory. The value is text. The exception is for style sheet links, where the title
attribute defines alternative style sheet sets.
The title
attribute on link
elements differs from the global title
attribute of most other elements in that a link without a title does not inherit the title of the parent element: it merely has no title.
The sizes
attribute is used with the icon
link type. The attribute must not be specified on link
elements that do not have a rel
attribute that specifies the icon
keyword.
The IDL attributes href
, rel
, media
, hreflang
, and type
, and sizes
each must reflect the respective content attributes of the same name.
The IDL attribute relList
reflect the rel
content attribute.
The IDL attribute disabled
only applies to style sheet links. When the link
element defines a style sheet link, then the disabled
attribute behaves as defined for the alternative style sheets DOM. For all other link
elements it always return false and does nothing on setting.
The LinkStyle
interface is also implemented by this element; the styling processing model defines how. [CSSOM]
Here, a set of link
elements provide some style sheets:
<!-- a persistent style sheet --> <link rel="stylesheet" href="default.css"> <!-- the preferred alternate style sheet --> <link rel="stylesheet" href="green.css" title="Green styles"> <!-- some alternate style sheets --> <link rel="alternate stylesheet" href="contrast.css" title="High contrast"> <link rel="alternate stylesheet" href="big.css" title="Big fonts"> <link rel="alternate stylesheet" href="wide.css" title="Wide screen">
The following example shows how you can specify versions of the page that use alternative formats, are aimed at other languages, and that are intended for other media:
<link rel=alternate href="/en/html" hreflang=en type=text/html title="English HTML"> <link rel=alternate href="/fr/html" hreflang=fr type=text/html title="French HTML"> <link rel=alternate href="/en/html/print" hreflang=en type=text/html media=print title="English HTML (for printing)"> <link rel=alternate href="/fr/html/print" hreflang=fr type=text/html media=print title="French HTML (for printing)"> <link rel=alternate href="/en/pdf" hreflang=en type=application/pdf title="English PDF"> <link rel=alternate href="/fr/pdf" hreflang=fr type=application/pdf title="French PDF">
meta
elementcharset
attribute is present, or if the element's http-equiv
attribute is in the Encoding declaration state: in a head
element.http-equiv
attribute is present but not in the Encoding declaration state: in a head
element.http-equiv
attribute is present but not in the Encoding declaration state: in a noscript
element that is a child of a head
element.name
attribute is present: where metadata content is expected.name
http-equiv
content
charset
interface HTMLMetaElement : HTMLElement { attribute DOMString name; attribute DOMString httpEquiv; attribute DOMString content; };
The meta
element represents various kinds of metadata that cannot be expressed using the title
, base
, link
, style
, and script
elements.
The meta
element can represent document-level metadata with the name
attribute, pragma directives with the http-equiv
attribute, and the file's character encoding declaration when an HTML document is serialized to string form (e.g. for transmission over the network or for disk storage) with the charset
attribute.
Exactly one of the name
, http-equiv
, and charset
attributes must be specified.
If either name
or http-equiv
is specified, then the content
attribute must also be specified. Otherwise, it must be omitted.
The charset
attribute specifies the character encoding used by the document. This is a character encoding declaration. If the attribute is present in an XML document, its value must be an ASCII case-insensitive match for the string "UTF-8
" (and the document is therefore forced to use UTF-8 as its encoding).
The charset
attribute on the meta
element has no effect in XML documents, and is only allowed in order to facilitate migration to and from XHTML.
There must not be more than one meta
element with a charset
attribute per document.
The content
attribute gives the value of the document metadata or pragma directive when the element is used for those purposes. The allowed values depend on the exact context, as described in subsequent sections of this specification.
If a meta
element has a name
attribute, it sets document metadata. Document metadata is expressed in terms of name/value pairs, the name
attribute on the meta
element giving the name, and the content
attribute on the same element giving the value. The name specifies what aspect of metadata is being set; valid names and the meaning of their values are described in the following sections. If a meta
element has no content
attribute, then the value part of the metadata name/value
pair is the empty string.
The name
and content
IDL attributes must reflect the respective content attributes of the same name. The IDL attribute httpEquiv
must reflect the content attribute http-equiv
.
This specification defines a few names for the name
attribute of the meta
element.
Names are case-insensitive.
application-name
The value must be a short free-form string giving the name of the Web application that the page represents. If the page is not a Web application, the application-name
metadata name must not be used. There must not be more than one meta
element with its name
attribute set to the value application-name
per document.
author
The value must be a free-form string giving the name of one of the page's authors.
description
The value must be a free-form string that describes the page. The value must be appropriate for use in a directory of pages, e.g. in a search engine. There must not be more than one meta
element with its name
attribute set to the value description
per document.
generator
The value must be a free-form string that identifies one of the software packages used to generate the document. This value must not be used on hand-authored pages.
Here is what a tool called "Frontweaver" could include in its output, in the page's head
element, to identify itself as the tool used to generate the page:
<meta name=generator content="Frontweaver 8.2">
keywords
The value must be a set of comma-separated tokens, each of which is a keyword relevant to the page.
This page about typefaces on British motorways uses a meta
element to specify some keywords that users might use to look for the page:
<!DOCTYPE HTML> <html> <head> <title>Typefaces on UK motorways</title> <meta name="keywords" content="british,type face,font,fonts,highway,highways"> </head> <body> ...
Many search engines do not consider such keywords, because this feature has historically been used unreliably and even misleadingly as a way to spam search engine results in a way that is not helpful for users.
Extensions to the predefined set of metadata names may be registered in the WHATWG Wiki MetaExtensions page. [WHATWGWIKI]
Anyone is free to edit the WHATWG Wiki MetaExtensions page at any time to add a type. These new names must be specified with the following information:
The actual name being defined. The name should not be confusingly similar to any other defined name (e.g. differing only in case).
A short non-normative description of what the metadata name's meaning is, including the format the value is required to be in.
A list of other names that have exactly the same processing requirements. Authors should not use the names defined to be synonyms, they are only intended to allow user agents to support legacy content. Anyone may remove synonyms that are not used in practice; only names that need to be processed as synonyms for compatibility with legacy content are to be registered in this way.
One of the following:
If a metadata name is found to be redundant with existing values, it should be removed and listed as a synonym for the existing value.
If a metadata name is registered in the "proposed" state for a period of a month or more without being used or specified, then it may be removed from the registry.
If a metadata name is added with the "proposed" status and found to be redundant with existing values, it should be removed and listed as a synonym for the existing value. If a metadata name is added with the "proposed" status and found to be harmful, then it should be changed to "discontinued" status.
Anyone can change the status at any time, but should only do so in accordance with the definitions above.
Metadata names whose values are to be URLs must not be proposed or accepted. Links must be represented using the link
element, not the meta
element.
When the http-equiv
attribute is specified on a meta
element, the element is a pragma directive.
The http-equiv
attribute is an enumerated attribute. The following table lists the keywords defined for this attribute. The states given in the first cell of the rows with keywords give the states to which those keywords map.
State | Keyword | Notes |
---|---|---|
Encoding declaration | content-type |
|
Default style | default-style |
|
Refresh | refresh |
http-equiv="content-type"
)The Encoding declaration state is just an alternative form of setting the charset
attribute: it is a character encoding declaration.
For meta
elements with an http-equiv
attribute in the Encoding declaration state, the content
attribute must have a value that is an ASCII case-insensitive match for a string that consists of: the literal string "text/html;
", optionally followed by any number of space characters, followed by the literal string "charset=
", followed by the character encoding name of the character encoding declaration.
A document must not contain both a meta
element with an http-equiv
attribute in the Encoding declaration state and a meta
element with the charset
attribute present.
The Encoding declaration state may be used in HTML documents, but elements with an http-equiv
attribute in that state must not be used in XML documents.
http-equiv="default-style"
)This pragma sets the name of the default alternative style sheet set.
http-equiv="refresh"
)This pragma acts as timed redirect.
For meta
elements with an http-equiv
attribute in the Refresh state, the content
attribute must have a value consisting either of:
URL
", followed by a U+003D EQUALS SIGN character (=), followed by a valid URL that does not start with a literal U+0027 APOSTROPHE (') or U+0022 QUOTATION MARK (") character.In the former case, the integer represents a number of seconds before the page is to be reloaded; in the latter case the integer represents a number of seconds before the page is to be replaced by the page at the given URL.
A news organization's front page could include the following markup in the page's head
element, to ensure that the page automatically reloads from the server every five minutes:
<meta http-equiv="Refresh" content="300">
A sequence of pages could be used as an automated slide show by making each page refresh to the next page in the sequence, using markup such as the following:
<meta http-equiv="Refresh" content="20; URL=page4.html">
There must not be more than one meta
element with any particular state in the document at a time.
Extensions to the predefined set of pragma directives may, under certain conditions, be registered in the WHATWG Wiki PragmaExtensions page. [WHATWGWIKI]
Such extensions must use a name that is identical to an HTTP header registered in the Permanent Message Header Field Registry, and must have behavior identical to that described for the HTTP header. [IANAPERMHEADERS]
Pragma directives corresponding to headers describing metadata, or not requiring specific user agent processing, must not be registered; instead, use metadata names. Pragma directives corresponding to headers that affect the HTTP processing model (e.g. caching) must not be registered, as they would result in HTTP-level behavior being different for user agents that implement HTML than for user agents that do not.
Anyone is free to edit the WHATWG Wiki PragmaExtensions page at any time to add a pragma directive satisfying these conditions. Such registrations must specify the following information:
The actual name being defined. The name must match a previously-registered HTTP name with the same requirements.
A short non-normative description of the purpose of the pragma directive.
A character encoding declaration is a mechanism by which the character encoding used to store or transmit a document is specified.
The following restrictions apply to character encoding declarations:
In addition, due to a number of restrictions on meta
elements, there can only be one meta
-based character encoding declaration per document.
If an HTML document does not start with a BOM, and if its encoding is not explicitly given by Content-Type metadata, and the document is not an iframe
srcdoc
document, then the character encoding used must be an ASCII-compatible character encoding, and, in addition, if that encoding isn't US-ASCII itself, then the encoding must be specified using a meta
element with a charset
attribute or a meta
element with an http-equiv
attribute in the Encoding declaration state.
If the document is an iframe
srcdoc
document, the document must not have a character encoding declaration. (In this case, the source is already decoded, since it is part of the document that contained the iframe
.)
If an HTML document contains a meta
element with a charset
attribute or a meta
element with an http-equiv
attribute in the Encoding declaration state, then the character encoding used must be an ASCII-compatible character encoding.
Authors are encouraged to use UTF-8. Conformance checkers may advise authors against using legacy encodings. [RFC3629]
Encodings in which a series of bytes in the range 0x20 to 0x7E can encode characters other than the corresponding characters in the range U+0020 to U+007E represent a potential security vulnerability: a user agent that does not support the encoding (or does not support the label used to declare the encoding, or does not use the same mechanism to detect the encoding of unlabelled content as another user agent) might end up interpreting technically benign plain text content as HTML tags and JavaScript. For example, this applies to encodings in which the bytes corresponding to "<script>
" in ASCII can encode a different string. Authors should not use such encodings, which are known to include JIS_C6226-1983, JIS_X0212-1990, HZ-GB-2312, JOHAB (Windows code page 1361), encodings based on ISO-2022, and encodings based on EBCDIC. Furthermore, authors must not use the CESU-8, UTF-7, BOCU-1 and SCSU encodings, which also fall into this category, because these
encodings were never intended for use for Web content. [RFC1345] [RFC1842]
[RFC1468]
[RFC2237]
[RFC1554]
[RFC1922] [RFC1557]
[CESU8] [UTF7] [BOCU1] [SCSU]
Authors should not use UTF-32, as the encoding detection algorithms described in this specification intentionally do not distinguish it from UTF-16. [UNICODE]
Using non-UTF-8 encodings can have unexpected results on form submission and URL encodings, which use the document's character encoding by default.
In XHTML, the XML declaration should be used for inline character encoding information, if necessary.
In HTML, to declare that the character encoding is UTF-8, the author could include the following markup near the top of the document (in the head
element):
<meta charset="utf-8">
In XML, the XML declaration would be used instead, at the very top of the markup:
<?xml version="1.0" encoding="utf-8"?>
style
elementscoped
attribute is present: flow content.scoped
attribute is absent: where metadata content is expected.scoped
attribute is absent: in a noscript
element that is a child of a head
element.scoped
attribute is present: where flow content is expected, but before any other flow content other than other style
elements and inter-element whitespace.type
attribute, but must match requirements described in prose below.media
type
scoped
title
attribute has special semantics on this element.interface HTMLStyleElement : HTMLElement {
attribute boolean disabled;
attribute DOMString media;
attribute DOMString type;
attribute boolean scoped;
};
HTMLStyleElement implements LinkStyle;
The style
element allows authors to embed style information in their documents. The style
element is one of several inputs to the styling processing model. The element does not represent content for the user.
The type
attribute gives the styling language. If the attribute is present, its value must be a valid MIME type that designates a styling language. The charset
parameter must not be specified. The default value for the type
attribute, which is used if the attribute is absent, is "text/css
". [RFC2318]
The media
attribute says which media the styles apply to. The value must be a valid media query.
The default, if the media
attribute is omitted, is "all
", meaning that by default styles apply to all media.
The scoped
attribute is a boolean attribute. If set, it indicates that the styles are intended just for the subtree rooted at the style
element's parent element, as opposed to the whole Document
.
The title
attribute on style
elements defines alternative style sheet sets. If the style
element has no title
attribute, then it has no title; the title
attribute of ancestors does not apply to the style
element. [CSSOM]
The title
attribute on style
elements, like the title
attribute on link
elements, differs from the global title
attribute in that a style
block without a title does not inherit the title of the parent element: it merely has no title.
The textContent
of a style
element must match the style
production in the following ABNF, the character set for which is Unicode. [ABNF]
style = no-c-start *( c-start no-c-end c-end no-c-start ) no-c-start = <any string that doesn't contain a substring that matches c-start > c-start = "<!--" no-c-end = <any string that doesn't contain a substring that matches c-end > c-end = "-->"
This specification does not specify a style system, but CSS is expected to be supported by most Web browsers. [CSS]
The media
, type
and scoped
IDL attributes must reflect the respective content attributes of the same name.
The disabled
IDL attribute behaves as defined for the alternative style sheets DOM.
The LinkStyle
interface is also implemented by this element; the styling processing model defines how. [CSSOM]
The following document has its emphasis styled as bright red text rather than italics text, while leaving titles of works and Latin words in their default italics. It shows how using appropriate elements enables easier restyling of documents.
<!DOCTYPE html> <html lang="en-US"> <head> <title>My favorite book</title> <style> body { color: black; background: white; } em { font-style: normal; color: red; } </style> </head> <body> <p>My <em>favorite</em> book of all time has <em>got</em> to be <cite>A Cat's Life</cite>. It is a book by P. Rahmel that talks about the <i lang="la">Felis Catus</i> in modern human society.</p> </body> </html>
The link
and style
elements can provide styling information for the user agent to use when rendering the document. The DOM Styling specification specifies what styling information is to be used by the user agent and how it is to be used. [CSSOM]
The style
and link
elements implement the LinkStyle
interface. [CSSOM]
Scripts allow authors to add interactivity to their documents.
Authors are encouraged to use declarative alternatives to scripting where possible, as declarative mechanisms are often more maintainable, and many users disable scripting.
For example, instead of using script to show or hide a section to show more details, the details
element could be used.
Authors are also encouraged to make their applications degrade gracefully in the absence of scripting support.
For example, if an author provides a link in a table header to dynamically resort the table, the link could also be made to function without scripts by requesting the sorted table from the server.
script
elementsrc
attribute, depends on the value of the type
attribute, but must match script content restrictions.src
attribute, the element must be either empty or contain only script documentation that also matches script content restrictions.src
async
defer
type
charset
interface HTMLScriptElement : HTMLElement { attribute DOMString src; attribute boolean async; attribute boolean defer; attribute DOMString type; attribute DOMString charset; attribute DOMString text; };
The script
element allows authors to include dynamic script and data blocks in their documents. The element does not represent content for the user.
When used to include dynamic scripts, the scripts may either be embedded inline or may be imported from an external file using the src
attribute. If the language is not that described by "text/javascript
", then the type
attribute must be present, as described below. Whatever language is used, the contents of the script
element must conform with the requirements of that language's specification.
When used to include data blocks (as opposed to scripts), the data must be embedded inline, the format of the data must be given using the type
attribute, the src
attribute must not be specified, and the contents of the script
element must conform to the requirements defined for the format used.
The type
attribute gives the language of the script or format of the data. If the attribute is present, its value must be a valid MIME type. The charset
parameter must not be specified. The default, which is used if the attribute is absent, is "text/javascript
".
The src
attribute, if specified, gives the address of the external script resource to use. The value of the attribute must be a valid non-empty URL potentially surrounded by spaces identifying a script resource of the type given by the type
attribute, if the attribute is present, or of the type "text/javascript
", if the attribute is absent. A resource is a script resource of a given type if that type identifies a scripting language and the resource conforms with the requirements of that language's specification.
The charset
attribute gives the character encoding of the external script resource. The attribute must not be specified if the src
attribute is not present. If the attribute is set, its value must be a valid character encoding name, must be an ASCII case-insensitive match for the preferred MIME name for that encoding, and must match the encoding given in the charset
parameter of the Content-Type metadata of the external file, if any. [IANACHARSET]
The async
and defer
attributes are boolean attributes that indicate how the script should be executed. The defer
and async
attributes must not be specified if the src
attribute is not present.
There are three possible modes that can be selected using these attributes. If the async
attribute is present, then the script will be executed asynchronously, as soon as it is available. If the async
attribute is not present but the defer
attribute is present, then the script is executed when the page has finished parsing. If neither attribute is present, then the script is fetched and executed immediately, before the user agent continues parsing the page.
The exact processing details for these attributes are, for mostly historical reasons, somewhat non-trivial, involving a number of aspects of HTML. The implementation requirements are therefore by necessity scattered throughout the specification. The algorithms below (in this section) describe the core of this processing, but these algorithms reference and are referenced by the parsing rules for script
start and end tags in HTML, in foreign content, and in XML, the rules for the document.write()
method, the handling of scripting, etc.
The defer
attribute may be specified even if the async
attribute is specified, to cause legacy Web browsers that only support defer
(and not async
) to fall back to the defer
behavior instead of the synchronous blocking behavior that is the default.
Changing the src
, type
, charset
, async
, and defer
attributes dynamically has no direct effect; these attribute are only used at specific times described below.
The IDL attributes src
, type
, charset
, and defer
, each must reflect the respective content attributes of the same name.
The async
IDL attribute controls whether the element will execute asynchronously or not. If the element's "force-async" flag is set, then, on getting, the async
IDL attribute must return true, and on setting, the "force-async" flag must first be unset, and then the content attribute must be removed if the IDL attribute's new value is false, and must be set to the empty string if the IDL attribute's new value is true. If the element's "force-async" flag is not set, the IDL attribute must reflect the async
content attribute.
text
[ = value ]Returns the contents of the element, ignoring child nodes that aren't text nodes.
Can be set, to replace the element's children with the given value.
When inserted using the document.write()
method, script
elements execute (typically synchronously), but when inserted using innerHTML
and outerHTML
attributes, they do not execute at all.
In this example, two script
elements are used. One embeds an external script, and the other includes some data.
<script src="game-engine.js"></script> <script type="text/x-game-map"> ........U.........e o............A....e .....A.....AAA....e .A..AAA...AAAAA...e </script>
The data in this case might be used by the script to generate the map of a video game. The data doesn't have to be used that way, though; maybe the map data is actually embedded in other parts of the page's markup, and the data block here is just used by the site's search engine to help users who are looking for particular features in their game maps.
The following sample shows how a script element can be used to define a function that is then used by other parts of the document. It also shows how a script
element can be used to invoke script while the document is being parsed, in this case to initialize the form's output.
<script> function calculate(form) { var price = 52000; if (form.elements.brakes.checked) price += 1000; if (form.elements.radio.checked) price += 2500; if (form.elements.turbo.checked) price += 5000; if (form.elements.sticker.checked) price += 250; form.elements.result.value = price; } </script> <form name="pricecalc" onsubmit="return false" onchange="calculate(this)"> <fieldset> <legend>Work out the price of your car</legend> <p>Base cost: £52000.</p> <p>Select additional options:</p> <ul> <li><label><input type=checkbox name=brakes> Ceramic brakes (£1000)</label></li> <li><label><input type=checkbox name=radio> Satellite radio (£2500)</label></li> <li><label><input type=checkbox name=turbo> Turbo charger (£5000)</label></li> <li><label><input type=checkbox name=sticker> "XZ" sticker (£250)</label></li> </ul> <p>Total: £<output name=result></output></p> </fieldset> <script> calculate(document.forms.pricecalc); </script> </form>
The following lists some MIME type strings and the languages to which they refer:
application/ecmascript
"application/javascript
"application/x-ecmascript
"application/x-javascript
"text/ecmascript
"text/javascript
"text/javascript1.0
"text/javascript1.1
"text/javascript1.2
"text/javascript1.3
"text/javascript1.4
"text/javascript1.5
"text/jscript
"text/livescript
"text/x-ecmascript
"text/x-javascript
"text/javascript;e4x=1
"script
elementsThe textContent
of a script
element must match the script
production in the following ABNF, the character set for which is Unicode. [ABNF]
script = data1 *( escape [ script-start data3 ] "-->" data1 ) [ escape ] escape = "<!--" data2 *( script-start data3 script-end data2 ) data1 = <any string that doesn't contain a substring that matches not-data1> not-data1 = "<!--" data2 = <any string that doesn't contain a substring that matches not-data2> not-data2 = script-start / "-->" data3 = <any string that doesn't contain a substring that matches not-data3> not-data3 = script-end / "-->" script-start = lt s c r i p t tag-end script-end = lt slash s c r i p t tag-end lt = %x003C ; U+003C LESS-THAN SIGN character (<) slash = %x002F ; U+002F SOLIDUS character (/) s = %x0053 ; U+0053 LATIN CAPITAL LETTER S s =/ %x0073 ; U+0073 LATIN SMALL LETTER S c = %x0043 ; U+0043 LATIN CAPITAL LETTER C c =/ %x0063 ; U+0063 LATIN SMALL LETTER C r = %x0052 ; U+0052 LATIN CAPITAL LETTER R r =/ %x0072 ; U+0072 LATIN SMALL LETTER R i = %x0049 ; U+0049 LATIN CAPITAL LETTER I i =/ %x0069 ; U+0069 LATIN SMALL LETTER I p = %x0050 ; U+0050 LATIN CAPITAL LETTER P p =/ %x0070 ; U+0070 LATIN SMALL LETTER P t = %x0054 ; U+0054 LATIN CAPITAL LETTER T t =/ %x0074 ; U+0074 LATIN SMALL LETTER T tag-end = %x0009 ; U+0009 CHARACTER TABULATION (tab) tag-end =/ %x000A ; U+000A LINE FEED (LF) tag-end =/ %x000C ; U+000C FORM FEED (FF) tag-end =/ %x0020 ; U+0020 SPACE tag-end =/ %x002F ; U+002F SOLIDUS (/) tag-end =/ %x003E ; U+003E GREATER-THAN SIGN (>)
When a script
element contains script documentation, there are further restrictions on the contents of the element, as described in the section below.
If a script
element's src
attribute is specified, then the contents of the script
element, if any, must be such that the value of the text
IDL attribute, which is derived from the element's contents, matches the documentation
production in the following ABNF, the character set for which is Unicode. [ABNF]
documentation = *( *( space / tab / comment ) [ line-comment ] newline ) comment = slash star *( not-star / star not-slash ) 1*star slash line-comment = slash slash *not-newline ; characters tab = %x0009 ; U+0009 CHARACTER TABULATION (tab) newline = %x000A ; U+000A LINE FEED (LF) space = %x0020 ; U+0020 SPACE star = %x002A ; U+002A ASTERISK (*) slash = %x002F ; U+002F SOLIDUS (/) not-newline = %x0000-0009 / %x000B-10FFFF ; a Unicode character other than U+000A LINE FEED (LF) not-star = %x0000-0029 / %x002B-10FFFF ; a Unicode character other than U+002A ASTERISK (*) not-slash = %x0000-002E / %x0030-10FFFF ; a Unicode character other than U+002F SOLIDUS (/)
This corresponds to putting the contents of the element in JavaScript comments.
This requirement is in addition to the earlier restrictions on the syntax of contents of script
elements.
This allows authors to include documentation, such as license information or API information, inside their documents while still referring to external script files. The syntax is constrained so that authors don't accidentally include what looks like valid script while also providing a src
attribute.
<script src="cool-effects.js"> // create new instances using: // var e = new Effect(); // start the effect using .play, stop using .stop: // e.play(); // e.stop(); </script>
noscript
elementhead
element of an HTML document, if there are no ancestor noscript
elements.noscript
elements.head
element: in any order, zero or more link
elements, zero or more style
elements, and zero or more meta
elements.head
element: transparent, but there must be no noscript
element descendants.HTMLElement
.The noscript
element represents nothing if scripting is enabled, and represents its children if scripting is disabled. It is used to present different markup to user agents that
support scripting and those that don't support scripting, by affecting how the document is parsed.
When used in HTML documents, the allowed content model is as follows:
head
element, if scripting is disabled for the noscript
elementThe noscript
element must contain only link
, style
, and meta
elements.
head
element, if scripting is enabled for the noscript
elementThe noscript
element must contain only text, except that invoking the HTML fragment parsing algorithm with the noscript
element as the context element and the text contents as the input must result in a list of nodes that consists only of link
, style
, and meta
elements that would be conforming if they were children of the noscript
element, and no parse errors.
head
elements, if scripting is disabled for the noscript
elementThe noscript
element's content model is transparent, with the additional restriction that a noscript
element must not have a noscript
element as an ancestor (that is, noscript
can't be nested).
head
elements, if scripting is enabled for the noscript
elementThe noscript
element must contain only text, except that the text must be such that running the following algorithm results in a conforming document with no noscript
elements and no script
elements, and such that no step in the algorithm causes an HTML parser to flag a parse error:
script
element from the document.noscript
element in the document. For every noscript
element in that list, perform the following steps:
noscript
element.noscript
element, and call these elements the before children.noscript
element, and call these elements the after children.noscript
element.innerHTML
attribute of the parent element to the value of s. (This, as a side-effect, causes the noscript
element to be removed from the document.)All these contortions are required because, for historical reasons, the noscript
element is handled differently by the HTML parser based on whether scripting was enabled or not when the parser was invoked.
The noscript
element must not be used in XML documents.
The noscript
element is only effective in the HTML syntax, it has no effect in the XHTML syntax.
In the following example, a noscript
element is used to provide fallback for a script.
<form action="calcSquare.php"> <p> <label for=x>Number</label>: <input id="x" name="x" type="number"> </p> <script> var x = document.getElementById('x'); var output = document.createElement('p'); output.textContent = 'Type a number; it will be squared right then!'; x.form.appendChild(output); x.form.onsubmit = function () { return false; } x.oninput = function () { var v = x.valueAsNumber; output.textContent = v + ' squared is ' + v * v; }; </script> <noscript> <input type=submit value="Calculate Square"> </noscript> </form>
When script is disabled, a button appears to do the calculation on the server side. When script is enabled, the value is computed on-the-fly instead.
The noscript
element is a blunt instrument. Sometimes, scripts might be enabled, but for some reason the page's script might fail. For this reason, it's generally better to avoid using noscript
, and to instead design the script to change the page from being a scriptless page to a scripted page on the fly, as in the next example:
<form action="calcSquare.php"> <p> <label for=x>Number</label>: <input id="x" name="x" type="number"> </p> <input id="submit" type=submit value="Calculate Square"> <script> var x = document.getElementById('x'); var output = document.createElement('p'); output.textContent = 'Type a number; it will be squared right then!'; x.form.appendChild(output); x.form.onsubmit = function () { return false; } x.oninput = function () { var v = x.valueAsNumber; output.textContent = v + ' squared is ' + v * v; }; var submit = document.getElementById('submit'); submit.parentNode.removeChild(submit); </script> </form>
The above technique is also useful in XHTML, since noscript
is not supported in the XHTML syntax.
The body, section, nav, article, aside, h1, h2, h3, h4, h5, h6, hgroup, header, footer, and address elements.
body
elementhtml
element.onafterprint
onbeforeprint
onbeforeunload
onblur
onerror
onfocus
onhashchange
onload
onmessage
onoffline
ononline
onpagehide
onpageshow
onpopstate
onredo
onresize
onscroll
onstorage
onundo
onunload
interface HTMLBodyElement : HTMLElement { attribute Function onafterprint; attribute Function onbeforeprint; attribute Function onbeforeunload; attribute Function onblur; attribute Function onerror; attribute Function onfocus; attribute Function onhashchange; attribute Function onload; attribute Function onmessage; attribute Function onoffline; attribute Function ononline; attribute Function onpopstate; attribute Function onpagehide; attribute Function onpageshow; attribute Function onredo; attribute Function onresize; attribute Function onscroll; attribute Function onstorage; attribute Function onundo; attribute Function onunload; };
The body
element represents the main content of the document.
In conforming documents, there is only one body
element. The document.body
IDL attribute provides scripts with easy access to a document's body
element.
The body
element exposes as event handler content attributes a number of the event handlers of the Window
object. It also mirrors their event handler IDL attributes.
The onblur
, onerror
, onfocus
, onload
, and onscroll
event handlers of the Window
object, exposed on the body
element, shadow the generic event handlers with the same names normally supported by HTML elements.
Thus, for example, a bubbling error
event fired on a child of the body element of a Document
would first trigger the onerror
event handler content attributes of that element, then that of the root html
element, and only then would it trigger the onerror
event handler content attribute on the body
element. This is because the event would bubble from the target, to the body
, to the html
, to the Document
, to the Window
, and the event handler on the body
is watching the Window
not the body
. A regular event listener attached
to the body
using addEventListener()
, however, would fire when the event bubbled through the body
and not when it reaches the Window
object.
This page updates an indicator to show whether or not the user is online:
<!DOCTYPE HTML> <html> <head> <title>Online or offline?</title> <script> function update(online) { document.getElementById('status').textContent = online ? 'Online' : 'Offline'; } </script> </head> <body ononline="update(true)" onoffline="update(false)" onload="update(navigator.onLine)"> <p>You are: <span id="status">(Unknown)</span></p> </body> </html>
section
elementformatBlock
candidate.HTMLElement
.The section
element represents a generic section of a document or application. A section, in this context, is a thematic grouping of content, typically with a heading.
Examples of sections would be chapters, the various tabbed pages in a tabbed dialog box, or the numbered sections of a thesis. A Web site's home page could be split into sections for an introduction, news items, and contact information.
Authors are encouraged to use the article
element instead of the section
element when it would make sense to syndicate the contents of the element.
The section
element is not a generic container element. When an element is needed for styling purposes or as a convenience for scripting, authors are encouraged to use the div
element instead. A general rule is that the section
element is appropriate only if the element's contents would be listed explicitly in the document's outline.
In the following example, we see an article (part of a larger Web page) about apples, containing two short sections.
<article> <hgroup> <h1>Apples</h1> <h2>Tasty, delicious fruit!</h2> </hgroup> <p>The apple is the pomaceous fruit of the apple tree.</p> <section> <h1>Red Delicious</h1> <p>These bright red apples are the most common found in many supermarkets.</p> </section> <section> <h1>Granny Smith</h1> <p>These juicy, green apples make a great filling for apple pies.</p> </section> </article>
Notice how the use of section
means that the author can use h1
elements throughout, without having to worry about whether a particular section is at the top level, the second level, the third level, and so on.
Here is a graduation programme with two sections, one for the list of people graduating, and one for the description of the ceremony.
<!DOCTYPE Html> <Html ><Head ><Title >Graduation Ceremony Summer 2022</Title ></Head ><Body ><H1 >Graduation</H1 ><Section ><H1 >Ceremony</H1 ><P >Opening Procession</P ><P >Speech by Validactorian</P ><P >Speech by Class President</P ><P >Presentation of Diplomas</P ><P >Closing Speech by Headmaster</P ></Section ><Section ><H1 >Graduates</H1 ><Ul ><Li >Molly Carpenter</Li ><Li >Anastasia Luccio</Li ><Li >Ebenezar McCoy</Li ><Li >Karrin Murphy</Li ><Li >Thomas Raith</Li ><Li >Susan Rodriguez</Li ></Ul ></Section ></Body ></Html>
nav
elementformatBlock
candidate.HTMLElement
.The nav
element represents a section of a page that links to other pages or to parts within the page: a section with navigation links.
Not all groups of links on a page need to be in a nav
element — the element is primarily intended for sections that consist of major navigation blocks. In particular, it is common for footers to have a short list of links to various pages of a site, such as the terms of service, the home page, and a copyright page. The footer
element alone is sufficient for such cases; while a nav
element can be used in such cases, it is usually unnecessary.
User agents (such as screen readers) that are targeted at users who can benefit from navigation information being omitted in the initial rendering, or who can benefit from navigation information being immediately available, can use this element as a way to determine what content on the page to initially skip and/or provide on request.
In the following example, the page has several places where links are present, but only one of those places is considered a navigation section.
<body> <header> <h1>Wake up sheeple!</h1> <p><a href="news.html">News</a> - <a href="blog.html">Blog</a> - <a href="forums.html">Forums</a></p> <p>Last Modified: <time>2009-04-01</time></p> <nav> <h1>Navigation</h1> <ul> <li><a href="articles.html">Index of all articles</a></li> <li><a href="today.html">Things sheeple need to wake up for today</a></li> <li><a href="successes.html">Sheeple we have managed to wake</a></li> </ul> </nav> </header> <div> <article> <header> <h1>My Day at the Beach</h1> </header> <div> <p>Today I went to the beach and had a lot of fun.</p> ...more content... </div> <footer> <p>Posted <time pubdate="" datetime="2009-10-10T14:36-08:00">Thursday</time>.</p> </footer> </article> ...more blog posts... </div> <footer> <p>Copyright © 2006 The Example Company</p> <p><a href="about.html">About</a> - <a href="policy.html">Privacy Policy</a> - <a href="contact.html">Contact Us</a></p> </footer> </body>
Notice the div
elements being used to wrap all the contents of the page other than the header and footer, and all the contents of the blog entry other than its header and footer.
In the following example, there are two nav
elements, one for primary navigation around the site, and one for secondary navigation around the page itself.
<body> <h1>The Wiki Center Of Exampland</h1> <nav> <ul> <li><a href="/">Home</a></li> <li><a href="/events">Current Events</a></li> ...more... </ul> </nav> <article> <header> <h1>Demos in Exampland</h1> <p>Written by A. N. Other.</p> </header> <nav> <ul> <li><a href="#public">Public demonstrations</a></li> <li><a href="#destroy">Demolitions</a></li> ...more... </ul> </nav> <div> <section id="public"> <h1>Public demonstrations</h1> <p>...more...</p> </section> <section id="destroy"> <h1>Demolitions</h1> <p>...more...</p> </section> ...more... </div> <footer> <p><a href="?edit">Edit</a> | <a href="?delete">Delete</a> | <a href="?Rename">Rename</a></p> </footer> </article> <footer> <p><small>© copyright 1998 Exampland Emperor</small></p> </footer> </body>
A nav
element doesn't have to contain a list, it can contain other kinds of content as well. In this navigation block, links are provided in prose:
<nav> <h1>Navigation</h1> <p>You are on my home page. To the north lies <a href="/blog">my blog</a>, from whence the sounds of battle can be heard. To the east you can see a large mountain, upon which many <a href="/school">school papers</a> are littered. Far up thus mountain you can spy a little figure who appears to be me, desperately scribbling a <a href="/school/thesis">thesis</a>.</p> <p>To the west are several exits. One fun-looking exit is labeled <a href="http://games.example.com/">"games"</a>. Another more boring-looking exit is labeled <a href="http://isp.example.net/">ISP™</a>.</p> <p>To the south lies a dark and dank <a href="/about">contacts page</a>. Cobwebs cover its disused entrance, and at one point you see a rat run quickly out of the page.</p> </nav>
article
elementformatBlock
candidate.HTMLElement
.The article
element represents a self-contained composition in a document, page, application, or site and that is, in principle, independently distributable or reusable, e.g. in syndication. This could be a forum post, a magazine or newspaper article, a blog entry, a user-submitted comment, an interactive widget or gadget, or any other independent item of content.
When article
elements are nested, the inner article
elements represent articles that are in principle related to the contents of the outer article. For instance, a blog entry on a site that accepts user-submitted comments could represent the comments as article
elements nested within the article
element for the blog entry.
Author information associated with an article
element (q.v. the address
element) does not apply to nested article
elements.
When used specifically with content to be redistributed in syndication, the article
element is similar in purpose to the entry
element in Atom. [ATOM]
The time
element's pubdate
attribute can be used to provide the publication date for an article
element.
This example shows a blog post using the article
element:
<article> <header> <h1>The Very First Rule of Life</h1> <p><time pubdate datetime="2009-10-09T14:28-08:00"></time></p> </header> <p>If there's a microphone anywhere near you, assume it's hot and sending whatever you're saying to the world. Seriously.</p> <p>...</p> <footer> <a href="?comments=1">Show comments...</a> </footer> </article>
Here is that same blog post, but showing some of the comments:
<article> <header> <h1>The Very First Rule of Life</h1> <p><time pubdate datetime="2009-10-09T14:28-08:00"></time></p> </header> <p>If there's a microphone anywhere near you, assume it's hot and sending whatever you're saying to the world. Seriously.</p> <p>...</p> <section> <h1>Comments</h1> <article> <footer> <p>Posted by: George Washington</p> <p><time pubdate datetime="2009-10-10T19:10-08:00"></time></p> </footer> <p>Yeah! Especially when talking about your lobbyist friends!</p> </article> <article> <footer> <p>Posted by: George Hammond</p> <p><time pubdate datetime="2009-10-10T19:15-08:00"></time></p> </footer> <p>Hey, you have the same first name as me.</p> </article> </section> </article>
Notice the use of footer
to give the information for each comment (such as who wrote it and when): the footer
element can appear at the start of its section when appropriate, such as in this case. (Using header
in this case wouldn't be wrong either; it's mostly a matter of authoring preference.)
aside
elementformatBlock
candidate.HTMLElement
.The aside
element represents a section of a page that consists of content that is tangentially related to the content around the aside
element, and which could be considered separate from that content. Such sections are often represented as sidebars in printed typography.
The element can be used for typographical effects like pull quotes or sidebars, for advertising, for groups of nav
elements, and for other content that is considered separate from the main content of the page.
It's not appropriate to use the aside
element just for parentheticals, since those are part of the main flow of the document.
The following example shows how an aside is used to mark up background material on Switzerland in a much longer news story on Europe.
<aside> <h1>Switzerland</h1> <p>Switzerland, a land-locked country in the middle of geographic Europe, has not joined the geopolitical European Union, though it is a signatory to a number of European treaties.</p> </aside>
The following example shows how an aside is used to mark up a pull quote in a longer article.
... <p>He later joined a large company, continuing on the same work. <q>I love my job. People ask me what I do for fun when I'm not at work. But I'm paid to do my hobby, so I never know what to answer. Some people wonder what they would do if they didn't have to work... but I know what I would do, because I was unemployed for a year, and I filled that time doing exactly what I do now.</q></p> <aside> <q> People ask me what I do for fun when I'm not at work. But I'm paid to do my hobby, so I never know what to answer. </q> </aside> <p>Of course his work — or should that be hobby? — isn't his only passion. He also enjoys other pleasures.</p> ...
The following extract shows how aside
can be used for blogrolls and other side content on a blog:
<body> <header> <h1>My wonderful blog</h1> <p>My tagline</p> </header> <aside> <!-- this aside contains two sections that are tangentially related to the page, namely, links to other blogs, and links to blog posts from this blog --> <nav> <h1>My blogroll</h1> <ul> <li><a href="http://blog.example.com/">Example Blog</a> </ul> </nav> <nav> <h1>Archives</h1> <ol reversed> <li><a href="/last-post">My last post</a> <li><a href="/first-post">My first post</a> </ol> </nav> </aside> <aside> <!-- this aside is tangentially related to the page also, it contains twitter messages from the blog author --> <h1>Twitter Feed</h1> <blockquote cite="http://twitter.example.net/t31351234"> I'm on vacation, writing my blog. </blockquote> <blockquote cite="http://twitter.example.net/t31219752"> I'm going to go on vacation soon. </blockquote> </aside> <article> <!-- this is a blog post --> <h1>My last post</h1> <p>This is my last post.</p> <footer> <p><a href="/last-post" rel=bookmark>Permalink</a> </footer> </article> <article> <!-- this is also a blog post --> <h1>My first post</h1> <p>This is my first post.</p> <aside> <!-- this aside is about the blog post, since it's inside the <article> element; it would be wrong, for instance, to put the blogroll here, since the blogroll isn't really related to this post specifically, only to the page as a whole --> <h1>Posting</h1> <p>While I'm thinking about it, I wanted to say something about posting. Posting is fun!</p> </aside> <footer> <p><a href="/first-post" rel=bookmark>Permalink</a> </footer> </article> <footer> <nav> <a href="/archives">Archives</a> — <a href="/about">About me</a> — <a href="/copyright">Copyright</a> </nav> </footer> </body>
h1
, h2
, h3
, h4
, h5
, and h6
elementsformatBlock
candidate.hgroup
element.interface HTMLHeadingElement : HTMLElement {};
These elements represent headings for their sections.
The semantics and meaning of these elements are defined in the section on headings and sections.
These elements have a rank given by the number in their name. The h1
element is said to have the highest rank, the h6
element has the lowest rank, and two elements with the same name have equal rank.
These two snippets are equivalent:
<body> <h1>Let's call it a draw(ing surface)</h1> <h2>Diving in</h2> <h2>Simple shapes</h2> <h2>Canvas coordinates</h2> <h3>Canvas coordinates diagram</h3> <h2>Paths</h2> </body>
<body> <h1>Let's call it a draw(ing surface)</h1> <section> <h1>Diving in</h1> </section> <section> <h1>Simple shapes</h1> </section> <section> <h1>Canvas coordinates</h1> <section> <h1>Canvas coordinates diagram</h1> </section> </section> <section> <h1>Paths</h1> </section> </body>
hgroup
elementformatBlock
candidate.h1
, h2
, h3
, h4
, h5
, and/or h6
elements.HTMLElement
.The hgroup
element represents the heading of a section. The element is used to group a set of h1
–h6
elements when the heading has multiple levels, such as subheadings, alternative titles, or taglines.
For the purposes of document summaries, outlines, and the like, the text of hgroup
elements is defined to be the text of the highest ranked h1
–h6
element descendant of the hgroup
element, if there are any such elements, and the first such element if there are multiple elements with that rank. If there are no such elements, then the text of the hgroup
element is the empty string.
Other elements of heading content in the hgroup
element indicate subheadings or subtitles.
The rank of an hgroup
element is the rank of the highest-ranked h1
–h6
element descendant of the hgroup
element, if there are any such elements, or otherwise the same as for an h1
element (the highest rank).
The section on headings and sections defines how hgroup
elements are assigned to individual sections.
Here are some examples of valid headings. In each case, the emphasized text represents the text that would be used as the heading in an application extracting heading data and ignoring subheadings.
<hgroup> <h1>The reality dysfunction</h1> <h2>Space is not the only void</h2> </hgroup>
<hgroup> <h1>Dr. Strangelove</h1> <h2>Or: How I Learned to Stop Worrying and Love the Bomb</h2> </hgroup>
The point of using hgroup
in these examples is to mask the h2
element (which acts as a secondary title) from the outline algorithm.
header
elementformatBlock
candidate.header
or footer
element descendants.HTMLElement
.The header
element represents a group of introductory or navigational aids.
A header
element is intended to usually contain the section's heading (an h1
–h6
element or an hgroup
element), but this is not required. The header
element can also be used to wrap a section's table of contents, a search form, or any relevant logos.
Here are some sample headers. This first one is for a game:
<header> <p>Welcome to...</p> <h1>Voidwars!</h1> </header>
The following snippet shows how the element can be used to mark up a specification's header:
<header> <hgroup> <h1>Scalable Vector Graphics (SVG) 1.2</h1> <h2>W3C Working Draft 27 October 2004</h2> </hgroup> <dl> <dt>This version:</dt> <dd><a href="http://www.w3.org/TR/2004/WD-SVG12-20041027/">http://www.w3.org/TR/2004/WD-SVG12-20041027/</a></dd> <dt>Previous version:</dt> <dd><a href="http://www.w3.org/TR/2004/WD-SVG12-20040510/">http://www.w3.org/TR/2004/WD-SVG12-20040510/</a></dd> <dt>Latest version of SVG 1.2:</dt> <dd><a href="http://www.w3.org/TR/SVG12/">http://www.w3.org/TR/SVG12/</a></dd> <dt>Latest SVG Recommendation:</dt> <dd><a href="http://www.w3.org/TR/SVG/">http://www.w3.org/TR/SVG/</a></dd> <dt>Editor:</dt> <dd>Dean Jackson, W3C, <a href="mailto:dean@w3.org">dean@w3.org</a></dd> <dt>Authors:</dt> <dd>See <a href="#authors">Author List</a></dd> </dl> <p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notic ... </header>
The header
element is not sectioning content; it doesn't introduce a new section.
In this example, the page has a page heading given by the h1
element, and two subsections whose headings are given by h2
elements. The content after the header
element is still part of the last subsection started in the header
element, because the header
element doesn't take part in the outline algorithm.
<body> <header> <h1>Little Green Guys With Guns</h1> <nav> <ul> <li><a href="/games">Games</a> <li><a href="/forum">Forum</a> <li><a href="/download">Download</a> </ul> </nav> <h2>Important News</h2> <!-- this starts a second subsection --> <!-- this is part of the subsection entitled "Important News" --> <p>To play today's games you will need to update your client.</p> <h2>Games</h2> <!-- this starts a third subsection --> </header> <p>You have three active games:</p> <!-- this is still part of the subsection entitled "Games" --> ...
footer
elementformatBlock
candidate.header
or footer
element descendants.HTMLElement
.The footer
element represents a footer for its nearest ancestor sectioning content or sectioning root element. A footer typically contains information about its section such as who wrote it, links to related documents, copyright data, and the like.
When the footer
element contains entire sections, they represent appendices, indexes, long colophons, verbose license agreements, and other such content.
Contact information for the author or editor of a section belongs in an address
element, possibly itself inside a footer
.
Footers don't necessarily have to appear at the end of a section, though they usually do.
When the nearest ancestor sectioning content or sectioning root element is the body element, then it applies to the whole page.
The footer
element is not sectioning content; it doesn't introduce a new section.
Here is a page with two footers, one at the top and one at the bottom, with the same content:
<body> <footer><a href="../">Back to index...</a></footer> <hgroup> <h1>Lorem ipsum</h1> <h2>The ipsum of all lorems</h2> </hgroup> <p>A dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p> <footer><a href="../">Back to index...</a></footer> </body>
Here is an example which shows the footer
element being used both for a site-wide footer and for a section footer.
<!DOCTYPE HTML> <HTML><HEAD> <TITLE>The Ramblings of a Scientist</TITLE> <BODY> <H1>The Ramblings of a Scientist</H1> <ARTICLE> <H1>Episode 15</H1> <VIDEO SRC="/fm/015.ogv" CONTROLS PRELOAD> <P><A HREF="/fm/015.ogv">Download video</A>.</P> </VIDEO> <FOOTER> <!-- footer for article --> <P>Published <TIME PUBDATE DATETIME="2009-10-21T18:26-07:00"></TIME></P> </FOOTER> </ARTICLE> <ARTICLE> <H1>My Favorite Trains</H1> <P>I love my trains. My favorite train of all time is a Köf.</P> <P>It is fun to see them pull some coal cars because they look so dwarfed in comparison.</P> <FOOTER> <!-- footer for article --> <P>Published <TIME PUBDATE DATETIME="2009-09-15T14:54-07:00"></TIME></P> </FOOTER> </ARTICLE> <FOOTER> <!-- site wide footer --> <NAV> <P><A HREF="/credits.html">Credits</A> — <A HREF="/tos.html">Terms of Service</A> — <A HREF="/index.html">Blog Index</A></P> </NAV> <P>Copyright © 2009 Gordon Freeman</P> </FOOTER> </BODY> </HTML>
Some site designs have what is sometimes referred to as "fat footers" — footers that contain a lot of material, including images, links to other articles, links to pages for sending feedback, special offers... in some ways, a whole "front page" in the footer.
This fragment shows the bottom of a page on a site with a "fat footer":
... <footer> <nav> <section> <h1>Articles</h1> <p><img src="somersaults.jpeg" alt=""> Go to the gym with our somersaults class! Our teacher Jim takes you through the paces in this two-part article. <a href="articles/somersaults/1">Part 1</a> · <a href="articles/somersaults/1">Part 2</a></p> <p><img src="kindplus.jpeg"> Tired of walking on the edge of a clif<!-- sic -->? Our guest writer Lara shows you how to bumble your way through the bars. <a href="articles/kindplus/1">Read more...</a></p> <p><img src="crisps.jpeg"> The chips are down, now all that's left is a potato. What can you do with it? <a href="articles/crisps/1">Read more...</a></p> </section> <ul> <li> <a href="/about">About us...</a> <li> <a href="/feedback">Send feedback!</a> <li> <a href="/sitemap">Sitemap</a> </ul> </nav> <p><small>Copyright © 2015 The Snacker — <a href="/tos">Terms of Service</a></small></p> </footer> </body>
address
elementformatBlock
candidate.header
, footer
, or address
element descendants.HTMLElement
.The address
element represents the contact information for its nearest article
or body
element ancestor. If that is the body element, then the contact information applies to the document as a whole.
For example, a page at the W3C Web site related to HTML might include the following contact information:
<ADDRESS> <A href="../People/Raggett/">Dave Raggett</A>, <A href="../People/Arnaud/">Arnaud Le Hors</A>, contact persons for the <A href="Activity">W3C HTML Activity</A> </ADDRESS>
The address
element must not be used to represent arbitrary addresses (e.g. postal addresses), unless those addresses are in fact the relevant contact information. (The p
element is the appropriate element for marking up postal addresses in general.)
The address
element must not contain information other than contact information.
For example, the following is non-conforming use of the address
element:
<ADDRESS>Last Modified: 1999/12/24 23:37:50</ADDRESS>
Typically, the address
element would be included along with other information in a footer
element.
In this example the footer contains contact information and a copyright notice.
<footer> <address> For more details, contact <a href="mailto:js@example.com">John Smith</a>. </address> <p><small>© copyright 2038 Example Corp.</small></p> </footer>
The h1
–h6
elements and the hgroup
element are headings.
The first element of heading content in an element of sectioning content represents the heading for that section. Subsequent headings of equal or higher rank start new (implied) sections, headings of lower rank start implied subsections that are part of the previous one. In both cases, the element represents the heading of the implied section.
Certain elements are said to be sectioning roots, including blockquote
and td
elements. These elements can have their own outlines, but the sections and headings inside these elements do not contribute to the outlines of their ancestors.
Sectioning content elements are always considered subsections of their nearest ancestor sectioning root or their nearest ancestor element of sectioning content, whichever is nearest, regardless of what implied sections other headings may have created.
For the following fragment:
<body> <h1>Foo</h1> <h2>Bar</h2> <blockquote> <h3>Bla</h3> </blockquote> <p>Baz</p> <h2>Quux</h2> <section> <h3>Thud</h3> </section> <p>Grunt</p> </body>
...the structure would be:
body
section, containing the "Grunt" paragraph)
section
section)Notice how the section
ends the earlier implicit section so that a later paragraph ("Grunt") is back at the top level.
Sections may contain headings of any rank, but authors are strongly encouraged to either use only h1
elements, or to use elements of the appropriate rank for the section's nesting level.
Authors are also encouraged to explicitly wrap sections in elements of sectioning content, instead of relying on the implicit sections generated by having multiple headings in one element of sectioning content.
For example, the following is correct:
<body> <h4>Apples</h4> <p>Apples are fruit.</p> <section> <h2>Taste</h2> <p>They taste lovely.</p> <h6>Sweet</h6> <p>Red apples are sweeter than green ones.</p> <h1>Color</h1> <p>Apples come in various colors.</p> </section> </body>
However, the same document would be more clearly expressed as:
<body> <h1>Apples</h1> <p>Apples are fruit.</p> <section> <h2>Taste</h2> <p>They taste lovely.</p> <section> <h3>Sweet</h3> <p>Red apples are sweeter than green ones.</p> </section> </section> <section> <h2>Color</h2> <p>Apples come in various colors.</p> </section> </body>
Both of the documents above are semantically identical and would produce the same outline in compliant user agents.
This third example is also semantically identical, and might be easier to maintain (e.g. if sections are often moved around in editing):
<body> <h1>Apples</h1> <p>Apples are fruit.</p> <section> <h1>Taste</h1> <p>They taste lovely.</p> <section> <h1>Sweet</h1> <p>Red apples are sweeter than green ones.</p> </section> </section> <section> <h1>Color</h1> <p>Apples come in various colors.</p> </section> </body>
The outline for a sectioning content element or a sectioning root element consists of a list of one or more potentially nested sections. A section is a container that corresponds to some nodes in the original DOM tree. Each section can have one heading associated with it, and can contain any number of further nested sections. (The sections in the outline aren't section
elements, though some may correspond to such elements — they are merely conceptual sections.)
The following markup fragment:
<body> <h1>A</h1> <p>B</p> <h2>C</h2> <p>D</p> <h2>E</h2> <p>F</p> </body>
...results in the following outline being created for the body
node (and thus the entire document):
Section created for body
node.
Associated with heading "A".
Also associated with paragraph "B".
Nested sections:
The p, hr, pre, blockquote, ol, ul, li, dl, dt, dd, figure, figcaption, and div elements.
p
elementformatBlock
candidate.interface HTMLParagraphElement : HTMLElement {};
The p
element represents a paragraph.
While paragraphs are usually represented in visual media by blocks of text that are physically separated from adjacent blocks through blank lines, a style sheet or user agent would be equally justified in presenting paragraph breaks in a different manner, for instance using inline pilcrows (¶).
The following examples are conforming HTML fragments:
<p>The little kitten gently seated himself on a piece of carpet. Later in his life, this would be referred to as the time the cat sat on the mat.</p>
<fieldset> <legend>Personal information</legend> <p> <label>Name: <input name="n"></label> <label><input name="anon" type="checkbox"> Hide from other users</label> </p> <p><label>Address: <textarea name="a"></textarea></label></p> </fieldset>
<p>There was once an example from Femley,<br> Whose markup was of dubious quality.<br> The validator complained,<br> So the author was pained,<br> To move the error from the markup to the rhyming.</p>
The p
element should not be used when a more specific element is more appropriate.
The following example is technically correct:
<section> <!-- ... --> <p>Last modified: 2001-04-23</p> <p>Author: fred@example.com</p> </section>
However, it would be better marked-up as:
<section> <!-- ... --> <footer>Last modified: 2001-04-23</footer> <address>Author: fred@example.com</address> </section>
Or:
<section> <!-- ... --> <footer> <p>Last modified: 2001-04-23</p> <address>Author: fred@example.com</address> </footer> </section>
hr
elementinterface HTMLHRElement : HTMLElement {};
The hr
element represents a paragraph-level thematic break, e.g. a scene change in a story, or a transition to another topic within a section of a reference book.
The following fictional extract from a project manual shows two sections that use the hr
element to separate topics within the section.
<section> <h1>Communication</h1> <p>There are various methods of communication. This section covers a few of the important ones used by the project.</p> <hr> <p>Communication stones seem to come in pairs and have mysterious properties:</p> <ul> <li>They can transfer thoughts in two directions once activated if used alone.</li> <li>If used with another device, they can transfer one's consciousness to another body.</li> <li>If both stones are used with another device, the consciousnesses switch bodies.</li> </ul> <hr> <p>Radios use the electromagnetic spectrum in the meter range and longer.</p> <hr> <p>Signal flares use the electromagnetic spectrum in the nanometer range.</p> </section> <section> <h1>Food</h1> <p>All food at the project is rationed:</p> <dl> <dt>Potatoes</dt> <dd>Two per day</dd> <dt>Soup</dt> <dd>One bowl per day</dd> </dl> <hr> <p>Cooking is done by the chefs on a set rotation.</p> </section>
There is no need for an hr
element between the sections themselves, since the section
elements and the h1
elements imply thematic changes themselves.
The following extract from Pandora's Star by Peter F. Hamilton shows two paragraphs that precede a scene change and the paragraph that follows it. The scene change, represented in the printed book by a gap containing a solitary centered star between the second and third paragraphs, is here represented using the hr
element.
<p>Dudley was ninety-two, in his second life, and fast approaching
time for another rejuvenation. Despite his body having the physical
age of a standard fifty-year-old, the prospect of a long degrading
campaign within academia was one he regarded with dread. For a
supposedly advanced civilization, the Intersolar Commonwearth could be
appallingly backward at times, not to mention cruel.</p>
<p><i>Maybe it won't be that bad</i>, he told himself. The lie was
comforting enough to get him through the rest of the night's
shift.</p>
<hr>
<p>The Carlton AllLander drove Dudley home just after dawn. Like the
astronomer, the vehicle was old and worn, but perfectly capable of
doing its job. It had a cheap diesel engine, common enough on a
semi-frontier world like Gralmond, although its drive array was a
thoroughly modern photoneural processor. With its high suspension and
deep-tread tyres it could plough along the dirt track to the
observatory in all weather and seasons, including the metre-deep snow
of Gralmond's winters.</p>
The hr
element does not affect the document's outline.
pre
elementformatBlock
candidate.interface HTMLPreElement : HTMLElement {};
The pre
element represents a block of preformatted text, in which structure is represented by typographic conventions rather than by elements.
In the HTML syntax, a leading newline character immediately following the pre
element start tag is stripped.
Some examples of cases where the pre
element could be used:
Authors are encouraged to consider how preformatted text will be experienced when the formatting is lost, as will be the case for users of speech synthesizers, braille displays, and the like. For cases like ASCII art, it is likely that an alternative presentation, such as a textual description, would be more universally accessible to the readers of the document.
To represent a block of computer code, the pre
element can be used with a code
element; to represent a block of computer output the pre
element can be used with a samp
element. Similarly, the kbd
element can be used within a pre
element to indicate text that the user is to enter.
In the following snippet, a sample of computer code is presented.
<p>This is the <code>Panel</code> constructor:</p> <pre><code>function Panel(element, canClose, closeHandler) { this.element = element; this.canClose = canClose; this.closeHandler = function () { if (closeHandler) closeHandler() }; }</code></pre>
In the following snippet, samp
and kbd
elements are mixed in the contents of a pre
element to show a session of Zork I.
<pre><samp>You are in an open field west of a big white house with a boarded front door. There is a small mailbox here. ></samp> <kbd>open mailbox</kbd> <samp>Opening the mailbox reveals: A leaflet. ></samp></pre>
The following shows a contemporary poem that uses the pre
element to preserve its unusual formatting, which forms an intrinsic part of the poem itself.
<pre> maxling it is with a heart heavy that i admit loss of a feline so loved a friend lost to the unknown (night) ~cdr 11dec07</pre>
blockquote
elementformatBlock
candidate.cite
interface HTMLQuoteElement : HTMLElement { attribute DOMString cite; };
The HTMLQuoteElement
interface is also used by the q
element.
The blockquote
element represents a section that is quoted from another source.
Content inside a blockquote
must be quoted from another source, whose address, if it has one, may be cited in the cite
attribute.
If the cite
attribute is present, it must be a valid URL potentially surrounded by spaces.
The cite
IDL attribute must reflect the element's cite
content attribute.
This next example shows the use of cite
alongside blockquote
:
<p>His next piece was the aptly named <cite>Sonnet 130</cite>:</p> <blockquote cite="http://quotes.example.org/s/sonnet130.html"> <p>My mistress' eyes are nothing like the sun,<br> Coral is far more red, than her lips red,<br> ...
This example shows how a forum post could use blockquote
to show what post a user is replying to. The article
element is used for each post, to mark up the threading.
<article> <h1><a href="http://bacon.example.com/?blog=109431">Bacon on a crowbar</a></h1> <article> <header><strong>t3yw</strong> 12 points 1 hour ago</header> <p>I bet a narwhal would love that.</p> <footer><a href="?pid=29578">permalink</a></footer> <article> <header><strong>greg</strong> 8 points 1 hour ago</header> <blockquote><p>I bet a narwhal would love that.</p></blockquote> <p>Dude narwhals don't eat bacon.</p> <footer><a href="?pid=29579">permalink</a></footer> <article> <header><strong>t3yw</strong> 15 points 1 hour ago</header> <blockquote> <blockquote><p>I bet a narwhal would love that.</p></blockquote> <p>Dude narwhals don't eat bacon.</p> </blockquote> <p>Next thing you'll be saying they don't get capes and wizard hats either!</p> <footer><a href="?pid=29580">permalink</a></footer> <article> <article> <header><strong>boing</strong> -5 points 1 hour ago</header> <p>narwhals are worse than ceiling cat</p> <footer><a href="?pid=29581">permalink</a></footer> </article> </article> </article> </article> <article> <header><strong>fred</strong> 1 points 23 minutes ago</header> <blockquote><p>I bet a narwhal would love that.</p></blockquote> <p>I bet they'd love to peel a banana too.</p> <footer><a href="?pid=29582">permalink</a></footer> </article> </article> </article>
This example shows the use of a blockquote
for short snippets, demonstrating that one does not have to use p
elements inside blockquote
elements:
<p>He began his list of "lessons" with the following:</p> <blockquote>One should never assume that his side of the issue will be recognized, let alone that it will be conceded to have merits.</blockquote> <p>He continued with a number of similar points, ending with:</p> <blockquote>Finally, one should be prepared for the threat of breakdown in negotiations at any given moment and not be cowed by the possiblity.</blockquote> <p>We shall now discuss these points...
Examples of how to represent a conversation are shown in a later section; it is not appropriate to use the cite
and blockquote
elements for this purpose.
ol
elementli
elements.reversed
start
type
interface HTMLOListElement : HTMLElement { attribute boolean reversed; attribute long start; attribute DOMString type; };
The ol
element represents a list of items, where the items have been intentionally ordered, such that changing the order would change the meaning of the document.
The items of the list are the li
element child nodes of the ol
element, in tree order.
The reversed
attribute is a boolean attribute. If present, it indicates that the list is a descending list (..., 3, 2, 1). If the attribute is omitted, the list is an ascending list (1, 2, 3, ...).
The start
attribute, if present, must be a valid integer giving the ordinal value of the first list item.
The type
attribute can be used to specify the kind of marker to use in the list, in the cases where that matters (e.g. because items are to be referenced by their number/letter). The attribute, if specified, must have a value that is a case-sensitive match for one of the characters given in the first cell of one of the rows of the following table.
Keyword | State | Description | Examples for values 1-3 and 3999-4001 | |||||||
---|---|---|---|---|---|---|---|---|---|---|
1 (U+0031) |
decimal | Decimal numbers | 1. | 2. | 3. | ... | 3999. | 4000. | 4001. | ... |
a (U+0061) |
lower-alpha | Lowercase latin alphabet | a. | b. | c. | ... | ewu. | ewv. | eww. | ... |
A (U+0041) |
upper-alpha | Uppercase latin alphabet | A. | B. | C. | ... | EWU. | EWV. | EWW. | ... |
i (U+0069) |
lower-roman | Lowercase roman numerals | i. | ii. | iii. | ... | mmmcmxcix. | i̅v̅. | i̅v̅i. | ... |
I (U+0049) |
upper-roman | Uppercase roman numerals | I. | II. | III. | ... | MMMCMXCIX. | I̅V̅. | I̅V̅I. | ... |
The reversed
, start
, and type
IDL attributes must reflect the respective content attributes of the same name. The start
IDL attribute has the same default as its content attribute.
The following markup shows a list where the order matters, and where the ol
element is therefore appropriate. Compare this list to the equivalent list in the ul
section to see an example of the same items using the ul
element.
<p>I have lived in the following countries (given in the order of when I first lived there):</p> <ol> <li>Switzerland <li>United Kingdom <li>United States <li>Norway </ol>
Note how changing the order of the list changes the meaning of the document. In the following example, changing the relative order of the first two items has changed the birthplace of the author:
<p>I have lived in the following countries (given in the order of when I first lived there):</p> <ol> <li>United Kingdom <li>Switzerland <li>United States <li>Norway </ol>
ul
elementli
elements.interface HTMLUListElement : HTMLElement {};
The ul
element represents a list of items, where the order of the items is not important — that is, where changing the order would not materially change the meaning of the document.
The items of the list are the li
element child nodes of the ul
element.
The following markup shows a list where the order does not matter, and where the ul
element is therefore appropriate. Compare this list to the equivalent list in the ol
section to see an example of the same items using the ol
element.
<p>I have lived in the following countries:</p> <ul> <li>Norway <li>Switzerland <li>United Kingdom <li>United States </ul>
Note that changing the order of the list does not change the meaning of the document. The items in the snippet above are given in alphabetical order, but in the snippet below they are given in order of the size of their current account balance in 2007, without changing the meaning of the document whatsoever:
<p>I have lived in the following countries:</p> <ul> <li>Switzerland <li>Norway <li>United Kingdom <li>United States </ul>
li
elementol
elements.ul
elements.menu
elements.ol
element: value
interface HTMLLIElement : HTMLElement { attribute long value; };
The li
element represents a list item. If its parent element is an ol
, ul
, or menu
element, then the element is an item of the parent element's list, as defined for those elements. Otherwise, the list item has no defined list-related relationship to any other li
element.
If the parent element is an ol
element, then the li
element has an ordinal value.
The value
attribute, if present, must be a valid integer giving the ordinal value of the list item.
The value
IDL attribute must reflect the value of the value
content attribute.
The following example, the top ten movies are listed (in reverse order). Note the way the list is given a title by using a figure
element and its figcaption
element.
<figure> <figcaption>The top 10 movies of all time</figcaption> <ol> <li value="10"><cite>Josie and the Pussycats</cite>, 2001</li> <li value="9"><cite lang="sh">Црна мачка, бели мачор</cite>, 1998</li> <li value="8"><cite>A Bug's Life</cite>, 1998</li> <li value="7"><cite>Toy Story</cite>, 1995</li> <li value="6"><cite>Monsters, Inc</cite>, 2001</li> <li value="5"><cite>Cars</cite>, 2006</li> <li value="4"><cite>Toy Story 2</cite>, 1999</li> <li value="3"><cite>Finding Nemo</cite>, 2003</li> <li value="2"><cite>The Incredibles</cite>, 2004</li> <li value="1"><cite>Ratatouille</cite>, 2007</li> </ol> </figure>
The markup could also be written as follows, using the reversed
attribute on the ol
element:
<figure> <figcaption>The top 10 movies of all time</figcaption> <ol reversed> <li><cite>Josie and the Pussycats</cite>, 2001</li> <li><cite lang="sh">Црна мачка, бели мачор</cite>, 1998</li> <li><cite>A Bug's Life</cite>, 1998</li> <li><cite>Toy Story</cite>, 1995</li> <li><cite>Monsters, Inc</cite>, 2001</li> <li><cite>Cars</cite>, 2006</li> <li><cite>Toy Story 2</cite>, 1999</li> <li><cite>Finding Nemo</cite>, 2003</li> <li><cite>The Incredibles</cite>, 2004</li> <li><cite>Ratatouille</cite>, 2007</li> </ol> </figure>
If the li
element is the child of a menu
element and itself has a child that defines a command, then the li
element will match the :enabled
and :disabled
pseudo-classes in the same way as the first such child element does.
dl
elementdt
elements followed by one or more dd
elements.interface HTMLDListElement : HTMLElement {};
The dl
element represents an association list consisting of zero or more name-value groups (a description list). Each group must consist of one or more names (dt
elements) followed by one or more values (dd
elements). Within a single dl
element, there should not be more than one dt
element for each name.
Name-value groups may be terms and definitions, metadata topics and values, questions and answers, or any other groups of name-value data.
The values within a group are alternatives; multiple paragraphs forming part of the same value must all be given within the same dd
element.
The order of the list of groups, and of the names and values within each group, may be significant.
In the following example, one entry ("Authors") is linked to two values ("John" and "Luke").
<dl> <dt> Authors <dd> John <dd> Luke <dt> Editor <dd> Frank </dl>
In the following example, one definition is linked to two terms.
<dl> <dt lang="en-US"> <dfn>color</dfn> </dt> <dt lang="en-GB"> <dfn>colour</dfn> </dt> <dd> A sensation which (in humans) derives from the ability of the fine structure of the eye to distinguish three differently filtered analyses of a view. </dd> </dl>
The following example illustrates the use of the dl
element to mark up metadata of sorts. At the end of the example, one group has two metadata labels ("Authors" and "Editors") and two values ("Robert Rothman" and "Daniel Jackson").
<dl> <dt> Last modified time </dt> <dd> 2004-12-23T23:33Z </dd> <dt> Recommended update interval </dt> <dd> 60s </dd> <dt> Authors </dt> <dt> Editors </dt> <dd> Robert Rothman </dd> <dd> Daniel Jackson </dd> </dl>
The following example shows the dl
element used to give a set of instructions. The order of the instructions here is important (in the other examples, the order of the blocks was not important).
<p>Determine the victory points as follows (use the first matching case):</p> <dl> <dt> If you have exactly five gold coins </dt> <dd> You get five victory points </dd> <dt> If you have one or more gold coins, and you have one or more silver coins </dt> <dd> You get two victory points </dd> <dt> If you have one or more silver coins </dt> <dd> You get one victory point </dd> <dt> Otherwise </dt> <dd> You get no victory points </dd> </dl>
The following snippet shows a dl
element being used as a glossary. Note the use of dfn
to indicate the word being defined.
<dl> <dt><dfn>Apartment</dfn>, n.</dt> <dd>An execution context grouping one or more threads with one or more COM objects.</dd> <dt><dfn>Flat</dfn>, n.</dt> <dd>A deflated tire.</dd> <dt><dfn>Home</dfn>, n.</dt> <dd>The user's login directory.</dd> </dl>
The dl
element is inappropriate for marking up dialogue. Examples of how to mark up dialogue are shown below.
dt
elementdd
or dt
elements inside dl
elements.HTMLElement
.The dt
element represents the term, or name, part of a term-description group in a description list (dl
element).
The dt
element itself, when used in a dl
element, does not indicate that its contents are a term being defined, but this can be indicated using the dfn
element.
This example shows a list of frequently asked questions (a FAQ) marked up using the dt
element for questions and the dd
element for answers.
<article> <h1>FAQ</h1> <dl> <dt>What do we want?</dt> <dd>Our data.</dd> <dt>When do we want it?</dt> <dd>Now.</dd> <dt>Where is it?</dt> <dd>We are not sure.</dd> </dl> </article>
dd
elementdt
or dd
elements inside dl
elements.HTMLElement
.The dd
element represents the description, definition, or value, part of a term-description group in a description list (dl
element).
A dl
can be used to define a vocabulary list, like in a dictionary. In the following example, each entry, given by a dt
with a dfn
, has several dd
s, showing the various parts of the definition.
<dl> <dt><dfn>happiness</dfn></dt> <dd class="pronunciation">/'hæ p. nes/</dd> <dd class="part-of-speech"><i><abbr>n.</abbr></i></dd> <dd>The state of being happy.</dd> <dd>Good fortune; success. <q>Oh <b>happiness</b>! It worked!</q></dd> <dt><dfn>rejoice</dfn></dt> <dd class="pronunciation">/ri jois'/</dd> <dd><i class="part-of-speech"><abbr>v.intr.</abbr></i> To be delighted oneself.</dd> <dd><i class="part-of-speech"><abbr>v.tr.</abbr></i> To cause one to be delighted.</dd> </dl>
figure
elementfigcaption
element followed by flow content.figcaption
element.HTMLElement
.The figure
element represents some flow content, optionally with a caption, that is self-contained and is typically referenced as a single unit from the main flow of the document.
The element can thus be used to annotate illustrations, diagrams, photos, code listings, etc, that are referred to from the main content of the document, but that could, without affecting the flow of the document, be moved away from that primary content, e.g. to the side of the page, to dedicated pages, or to an appendix.
The figcaption
element child of the element, if any, represents the caption of the figure
element's contents. If there is no child figcaption
element, then there is no caption.
This example shows the figure
element to mark up a code listing.
<p>In <a href="#l4">listing 4</a> we see the primary core interface API declaration.</p> <figure id="l4"> <figcaption>Listing 4. The primary core interface API declaration.</figcaption> <pre><code>interface PrimaryCore { boolean verifyDataLine(); void sendData(in sequence<byte> data); void initSelfDestruct(); }</code></pre> </figure> <p>The API is designed to use UTF-8.</p>
Here we see a figure
element to mark up a photo.
<figure> <img src="bubbles-work.jpeg" alt="Bubbles, sitting in his office chair, works on his latest project intently."> <figcaption>Bubbles at work</figcaption> </figure>
In this example, we see an image that is not a figure, as well as an image and a video that are.
<h2>Malinko's comics</h2> <p>This case centered on some sort of "intellectual property" infringement related to a comic (see Exhibit A). The suit started after a trailer ending with these words: <blockquote> <img src="promblem-packed-action.png" alt="ROUGH COPY! Promblem-Packed Action!"> </blockquote> <p>...was aired. A lawyer, armed with a Bigger Notebook, launched a preemptive strike using snowballs. A complete copy of the trailer is included with Exhibit B. <figure> <img src="ex-a.png" alt="Two squiggles on a dirty piece of paper."> <figcaption>Exhibit A. The alleged <cite>rough copy</cite> comic.</figcaption> </figure> <figure> <video src="ex-b.mov"></video> <figcaption>Exhibit B. The <cite>Rough Copy</cite> trailer.</figcaption> </figure> <p>The case was resolved out of court.
Here, a part of a poem is marked up using figure
.
<figure> <p>'Twas brillig, and the slithy toves<br> Did gyre and gimble in the wabe;<br> All mimsy were the borogoves,<br> And the mome raths outgrabe.</p> <figcaption><cite>Jabberwocky</cite> (first verse). Lewis Carroll, 1832-98</figcaption> </figure>
In this example, which could be part of a much larger work discussing a castle, the figure has three images in it.
<figure> <img src="castle1423.jpeg" title="Etching. Anonymous, ca. 1423." alt="The castle has one tower, and a tall wall around it."> <img src="castle1858.jpeg" title="Oil-based paint on canvas. Maria Towle, 1858." alt="The castle now has two towers and two walls."> <img src="castle1999.jpeg" title="Film photograph. Peter Jankle, 1999." alt="The castle lies in ruins, the original tower all that remains in one piece."> <figcaption>The castle through the ages: 1423, 1858, and 1999 respectively.</figcaption> </figure>
figcaption
elementfigure
element.HTMLElement
.The figcaption
element represents a caption or legend for the rest of the contents of the figcaption
element's parent figure
element.
div
elementformatBlock
candidate.interface HTMLDivElement : HTMLElement {};
The div
element has no special meaning at all. It represents its children. It can be used with the class
, lang
, and title
attributes to mark up semantics common to a group of consecutive elements.
Authors are strongly encouraged to view the div
element as an element of last resort, for when no other element is suitable. Use of the div
element instead of more appropriate elements leads to poor accessibility for readers and poor maintainability for authors.
For example, a blog post would be marked up using article
, a chapter using section
, a page's navigation aids using nav
, and a group of form controls using fieldset
.
On the other hand, div
elements can be useful for stylistic purposes or to wrap multiple paragraphs within a section that are all to be annotated in a similar way. In the following example, we see div
elements used as a way to set the language of two paragraphs at once, instead of setting the language on the two paragraph elements separately:
<article lang="en-US"> <h1>My use of language and my cats</h1> <p>My cat's behavior hasn't changed much since her absence, except that she plays her new physique to the neighbors regularly, in an attempt to get pets.</p> <div lang="en-GB"> <p>My other cat, coloured black and white, is a sweetie. He followed us to the pool today, walking down the pavement with us. Yesterday he apparently visited our neighbours. I wonder if he recognises that their flat is a mirror image of ours.</p> <p>Hm, I just noticed that in the last paragraph I used British English. But I'm supposed to write in American English. So I shouldn't say "pavement" or "flat" or "colour"...</p> </div> <p>I should say "sidewalk" and "apartment" and "color"!</p> </article>
The a, em, strong, small, s, cite, q, dfn, abbr, time, code, figure, samp, kbd, sub, sup, i, b, u, mark, ruby, rt, rp, bdi, bdo, span, br, and wbr elements.
a
elementhref
target
rel
media
hreflang
type
interface HTMLAnchorElement : HTMLElement { stringifier attribute DOMString href; attribute DOMString target; attribute DOMString rel; readonly attribute DOMTokenList relList; attribute DOMString media; attribute DOMString hreflang; attribute DOMString type; attribute DOMString text; // URL decomposition IDL attributes attribute DOMString protocol; attribute DOMString host; attribute DOMString hostname; attribute DOMString port; attribute DOMString pathname; attribute DOMString search; attribute DOMString hash; };
If the a
element has an href
attribute, then it represents a hyperlink (a hypertext anchor).
If the a
element has no href
attribute, then the element represents a placeholder for where a link might otherwise have been placed, if it had been relevant.
The target
, rel
, media
, hreflang
, and type
attributes must be omitted if the href
attribute is not present.
If a site uses a consistent navigation toolbar on every page, then the link that would normally link to the page itself could be marked up using an a
element:
<nav> <ul> <li> <a href="/">Home</a> </li> <li> <a href="/news">News</a> </li> <li> <a>Examples</a> </li> <li> <a href="/legal">Legal</a> </li> </ul> </nav>
text
Same as textContent
.
The IDL attributes href
, target
, rel
, media
, hreflang
, and type
, must reflect the respective content attributes of the same name.
The IDL attribute relList
must reflect the rel
content attribute.
The a
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.
The a
element may be wrapped around entire paragraphs, lists, tables, and so forth, even entire sections, so long as there is no interactive content within (e.g. buttons or other links). This example shows how this can be used to make an entire advertising block into a link:
<aside class="advertising"> <h1>Advertising</h1> <a href="http://ad.example.com/?adid=1929&pubid=1422"> <section> <h1>Mellblomatic 9000!</h1> <p>Turn all your widgets into mellbloms!</p> <p>Only $9.99 plus shipping and handling.</p> </section> </a> <a href="http://ad.example.com/?adid=375&pubid=1422"> <section> <h1>The Mellblom Browser</h1> <p>Web browsing at the speed of light.</p> <p>No other browser goes faster!</p> </section> </a> </aside>
em
elementHTMLElement
.The em
element represents stress emphasis of its contents.
The level of emphasis that a particular piece of content has is given by its number of ancestor em
elements.
The placement of emphasis changes the meaning of the sentence. The element thus forms an integral part of the content. The precise way in which emphasis is used in this way depends on the language.
These examples show how changing the emphasis changes the meaning. First, a general statement of fact, with no emphasis:
<p>Cats are cute animals.</p>
By emphasizing the first word, the statement implies that the kind of animal under discussion is in question (maybe someone is asserting that dogs are cute):
<p><em>Cats</em> are cute animals.</p>
Moving the emphasis to the verb, one highlights that the truth of the entire sentence is in question (maybe someone is saying cats are not cute):
<p>Cats <em>are</em> cute animals.</p>
By moving it to the adjective, the exact nature of the cats is reasserted (maybe someone suggested cats were mean animals):
<p>Cats are <em>cute</em> animals.</p>
Similarly, if someone asserted that cats were vegetables, someone correcting this might emphasize the last word:
<p>Cats are cute <em>animals</em>.</p>
By emphasizing the entire sentence, it becomes clear that the speaker is fighting hard to get the point across. This kind of emphasis also typically affects the punctuation, hence the exclamation mark here.
<p><em>Cats are cute animals!</em></p>
Anger mixed with emphasizing the cuteness could lead to markup such as:
<p><em>Cats are <em>cute</em> animals!</em></p>
The em
element isn't a generic "italics" element. Sometimes, text is intended to stand out from the rest of the paragraph, as if it was in a different mood or voice. For this, the i
element is more appropriate.
The em
element also isn't intended to convey importance; for that purpose, the strong
element is more appropriate.
strong
elementHTMLElement
.The strong
element represents strong importance for its contents.
The relative level of importance of a piece of content is given by its number of ancestor strong
elements; each strong
element increases the importance of its contents.
Changing the importance of a piece of text with the strong
element does not change the meaning of the sentence.
Here is an example of a warning notice in a game, with the various parts marked up according to how important they are:
<p><strong>Warning.</strong> This dungeon is dangerous. <strong>Avoid the ducks.</strong> Take any gold you find. <strong><strong>Do not take any of the diamonds</strong>, they are explosive and <strong>will destroy anything within ten meters.</strong></strong> You have been warned.</p>
small
elementHTMLElement
.The small
element represents side comments such as small print.
Small print typically features disclaimers, caveats, legal restrictions, or copyrights. Small print is also sometimes used for attribution, or for satisfying licensing requirements.
The small
element does not "de-emphasize" or lower the importance of text emphasized by the em
element or marked as important with the strong
element. To mark text as not emphasized or important, simply do not mark it up with the em
or strong
elements respectively.
The small
element should not be used for extended spans of text, such as multiple paragraphs, lists, or sections of text. It is only intended for short runs of text. The text of a page listing terms of use, for instance, would not be a suitable candidate for the small
element: in such a case, the text is not a side comment, it is the main content of the page.
In this example, the small
element is used to indicate that value-added tax is not included in a price of a hotel room:
<dl> <dt>Single room <dd>199 € <small>breakfast included, VAT not included</small> <dt>Double room <dd>239 € <small>breakfast included, VAT not included</small> </dl>
In this second example, the small
element is used for a side comment in an article.
<p>Example Corp today announced record profits for the second quarter <small>(Full Disclosure: Foo News is a subsidiary of Example Corp)</small>, leading to speculation about a third quarter merger with Demo Group.</p>
This is distinct from a sidebar, which might be multiple paragraphs long and is removed from the main flow of text. In the following example, we see a sidebar from the same article. This sidebar also has small print, indicating the source of the information in the sidebar.
<aside> <h1>Example Corp</h1> <p>This company mostly creates small software and Web sites.</p> <p>The Example Corp company mission is "To provide entertainment and news on a sample basis".</p> <p><small>Information obtained from <a href="http://example.com/about.html">example.com</a> home page.</small></p> </aside>
In this last example, the small
element is marked as being important small print.
<p><strong><small>Continued use of this service will result in a kiss.</small></strong></p>
s
elementHTMLElement
.The s
element represents contents that are no longer accurate or no longer relevant.
The s
element is not appropriate when indicating document edits; to mark a span of text as having been removed from a document, use the del
element.
In this example a recommended retail price has been marked as no longer relevant as the product in question has a new sale price.
<p>Buy our Iced Tea and Lemonade!</p> <p><s>Recommended retail price: $3.99 per bottle</s></p> <p><strong>Now selling for just $2.99 a bottle!</strong></p>
cite
elementHTMLElement
.The cite
element represents the title of a work (e.g. a book, a paper, an essay, a poem, a score, a song, a script, a film, a TV show, a game, a sculpture, a painting, a theatre production, a play, an opera, a musical, an exhibition, a legal case report, etc). This can be a work that is being quoted or referenced in detail (i.e. a citation), or it can just be a work that is mentioned in passing.
A person's name is not the title of a work — even if people call that person a piece of work — and the element must therefore not be used to mark up people's names. (In some cases, the b
element might be appropriate for names; e.g. in a gossip article where the names of famous people are keywords rendered with a different style to draw attention to them. In other cases, if an element is really needed, the span
element can be used.)
This next example shows a typical use of the cite
element:
<p>My favorite book is <cite>The Reality Dysfunction</cite> by Peter F. Hamilton. My favorite comic is <cite>Pearls Before Swine</cite> by Stephan Pastis. My favorite track is <cite>Jive Samba</cite> by the Cannonball Adderley Sextet.</p>
This is correct usage:
<p>According to the Wikipedia article <cite>HTML</cite>, as it stood in mid-February 2008, leaving attribute values unquoted is unsafe. This is obviously an over-simplification.</p>
The following, however, is incorrect usage, as the cite
element here is containing far more than the title of the work:
<!-- do not copy this example, it is an example of bad usage! --> <p>According to <cite>the Wikipedia article on HTML</cite>, as it stood in mid-February 2008, leaving attribute values unquoted is unsafe. This is obviously an over-simplification.</p>
The cite
element is obviously a key part of any citation in a bibliography, but it is only used to mark the title:
<p><cite>Universal Declaration of Human Rights</cite>, United Nations, December 1948. Adopted by General Assembly resolution 217 A (III).</p>
A citation is not a quote (for which the q
element is appropriate).
This is incorrect usage, because cite
is not for quotes:
<p><cite>This is wrong!</cite>, said Ian.</p>
This is also incorrect usage, because a person is not a work:
<p><q>This is still wrong!</q>, said <cite>Ian</cite>.</p>
The correct usage does not use a cite
element:
<p><q>This is correct</q>, said Ian.</p>
As mentioned above, the b
element might be relevant for marking names as being keywords in certain kinds of documents:
<p>And then <b>Ian</b> said <q>this might be right, in a gossip column, maybe!</q>.</p>
q
elementcite
HTMLQuoteElement
.The q
element represents some phrasing content quoted from another source.
Quotation punctuation (such as quotation marks) that is quoting the contents of the element must not appear immediately before, after, or inside q
elements; they will be inserted into the rendering by the user agent.
Content inside a q
element must be quoted from another source, whose address, if it has one, may be cited in the cite
attribute. The source may be fictional, as when quoting characters in a novel or screenplay.
If the cite
attribute is present, it must be a valid URL potentially surrounded by spaces.
The q
element must not be used in place of quotation marks that do not represent quotes; for example, it is inappropriate to use the q
element for marking up sarcastic statements.
The use of q
elements to mark up quotations is entirely optional; using explicit quotation punctuation without q
elements is just as correct.
Here is a simple example of the use of the q
element:
<p>The man said <q>Things that are impossible just take longer</q>. I disagreed with him.</p>
Here is an example with both an explicit citation link in the q
element, and an explicit citation outside:
<p>The W3C page <cite>About W3C</cite> says the W3C's mission is <q cite="http://www.w3.org/Consortium/">To lead the World Wide Web to its full potential by developing protocols and guidelines that ensure long-term growth for the Web</q>. I disagree with this mission.</p>
In the following example, the quotation itself contains a quotation:
<p>In <cite>Example One</cite>, he writes <q>The man said <q>Things that are impossible just take longer</q>. I disagreed with him</q>. Well, I disagree even more!</p>
In the following example, quotation marks are used instead of the q
element:
<p>His best argument was ❝I disagree❞, which I thought was laughable.</p>
In the following example, there is no quote — the quotation marks are used to name a word. Use of the q
element in this case would be inappropriate.
<p>The word "ineffable" could have been used to describe the disaster resulting from the campaign's mismanagement.</p>
dfn
elementdfn
element descendants.title
attribute has special semantics on this element.HTMLElement
.The dfn
element represents the defining instance of a term. The paragraph, description list group, or section that is the nearest ancestor of the dfn
element must also contain the definition(s) for the term given by the dfn
element.
Defining term: If the dfn
element has a title
attribute, then the exact value of that attribute is the term being defined. Otherwise, if it contains exactly one element child node and no child text nodes, and that child element is an abbr
element with a title
attribute, then the exact value of that attribute is the term being defined. Otherwise, it is the exact textContent
of the dfn
element that gives the term being defined.
If the title
attribute of the dfn
element is present, then it must contain only the term being defined.
The title
attribute of ancestor elements does not affect dfn
elements.
An a
element that links to a dfn
element represents an instance of the term defined by the dfn
element.
In the following fragment, the term "GDO" is first defined in the first paragraph, then used in the second.
<p>The <dfn><abbr title="Garage Door Opener">GDO</abbr></dfn> is a device that allows off-world teams to open the iris.</p> <!-- ... later in the document: --> <p>Teal'c activated his <abbr title="Garage Door Opener">GDO</abbr> and so Hammond ordered the iris to be opened.</p>
With the addition of an a
element, the reference can be made explicit:
<p>The <dfn id=gdo><abbr title="Garage Door Opener">GDO</abbr></dfn> is a device that allows off-world teams to open the iris.</p> <!-- ... later in the document: --> <p>Teal'c activated his <a href=#gdo><abbr title="Garage Door Opener">GDO</abbr></a> and so Hammond ordered the iris to be opened.</p>
abbr
elementtitle
attribute has special semantics on this element.HTMLElement
.The abbr
element represents an abbreviation or acronym, optionally with its expansion. The title
attribute may be used to provide an expansion of the abbreviation. The attribute, if specified, must contain an expansion of the abbreviation, and nothing else.
The paragraph below contains an abbreviation marked up with the abbr
element. This paragraph defines the term "Web Hypertext Application Technology Working Group".
<p>The <dfn id=whatwg><abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr></dfn> is a loose unofficial collaboration of Web browser manufacturers and interested parties who wish to develop new technologies designed to allow authors to write and deploy Applications over the World Wide Web.</p>
An alternative way to write this would be:
<p>The <dfn id=whatwg>Web Hypertext Application Technology Working Group</dfn> (<abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr>) is a loose unofficial collaboration of Web browser manufacturers and interested parties who wish to develop new technologies designed to allow authors to write and deploy Applications over the World Wide Web.</p>
This paragraph has two abbreviations. Notice how only one is defined; the other, with no expansion associated with it, does not use the abbr
element.
<p>The <abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr> started working on HTML5 in 2004.</p>
This paragraph links an abbreviation to its definition.
<p>The <a href="#whatwg"><abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr></a> community does not have much representation from Asia.</p>
This paragraph marks up an abbreviation without giving an expansion, possibly as a hook to apply styles for abbreviations (e.g. smallcaps).
<p>Philip` and Dashiva both denied that they were going to get the issue counts from past revisions of the specification to backfill the <abbr>WHATWG</abbr> issue graph.</p>
If an abbreviation is pluralized, the expansion's grammatical number (plural vs singular) must match the grammatical number of the contents of the element.
Here the plural is outside the element, so the expansion is in the singular:
<p>Two <abbr title="Working Group">WG</abbr>s worked on this specification: the <abbr>WHATWG</abbr> and the <abbr>HTMLWG</abbr>.</p>
Here the plural is inside the element, so the expansion is in the plural:
<p>Two <abbr title="Working Groups">WGs</abbr> worked on this specification: the <abbr>WHATWG</abbr> and the <abbr>HTMLWG</abbr>.</p>
Abbreviations do not have to be marked up using this element. It is expected to be useful in the following cases:
abbr
element with a title
attribute is an alternative to including the expansion inline (e.g. in parentheses).abbr
element with a title
attribute or include the expansion inline in the text the first time the abbreviation is used.abbr
element can be used without a title
attribute.Providing an expansion in a title
attribute once will not necessarily cause other abbr
elements in the same document with the same contents but without a title
attribute to behave as if they had the same expansion. Every abbr
element is independent.
time
elementtime
element descendants.datetime
pubdate
interface HTMLTimeElement : HTMLElement { attribute DOMString dateTime; attribute boolean pubDate; readonly attribute Date valueAsDate; };
The time
element represents either a time on a 24 hour clock, or a precise date in the proleptic Gregorian calendar, optionally with a time and a time-zone offset. [GREGORIAN]
This element is intended as a way to encode modern dates and times in a machine-readable way so that, for example, user agents can offer to add birthday reminders or scheduled events to the user's calendar.
The time
element is not intended for encoding times for which a precise date or time cannot be established. For example, it would be inappropriate for encoding times like "one millisecond after the big bang", "the early part of the Jurassic period", or "a winter around 250 BCE".
For dates before the introduction of the Gregorian calendar, authors are encouraged to not use the time
element, or else to be very careful about converting dates and times from the period to the Gregorian calendar. This is complicated by the manner in which the Gregorian calendar was phased in, which occurred at different times in different countries, ranging from partway through the 16th century all the way to early in the 20th.
The pubdate
attribute is a boolean attribute. If specified, it indicates that the date and time given by the element is the publication date and time of the nearest ancestor article
element, or, if the element has no ancestor article
element, of the document as a whole. If the element has a pubdate
attribute specified, then the element needs a date. For each article
element, there must be no more than one time
element with a
pubdate
attribute whose nearest ancestor is that article
element. Furthermore, for each Document
, there must be no more than one time
element with a pubdate
attribute that does not have an ancestor article
element.
The datetime
attribute, if present, gives the date or time being specified. Otherwise, the date or time is given by the element's contents.
If the element needs a date, and the datetime
attribute is present, then the attribute's value must be a valid date string with optional time.
If the element needs a date, but the datetime
attribute is not present, then the element's textContent
must be a valid date string in content with optional time.
If the element does not need a date, and the datetime
attribute is present, then the attribute's value must be a valid date or time string.
If the element does not need a date, but the datetime
attribute is not present, then the element's textContent
must be a valid date or time string in content.
The date, if any, must be expressed using the Gregorian calendar.
The time
element can be used to encode dates, for example in Microformats. The following shows a hypothetical way of encoding an event using a variant on hCalendar that uses the time
element:
<div class="vevent"> <a class="url" href="http://www.web2con.com/">http://www.web2con.com/</a> <span class="summary">Web 2.0 Conference</span>: <time class="dtstart" datetime="2007-10-05">October 5</time> - <time class="dtend" datetime="2007-10-20">19</time>, at the <span class="location">Argent Hotel, San Francisco, CA</span> </div>
(The end date is encoded as one day after the last date of the event because in the iCalendar format, end dates are exclusive, not inclusive.)
The time
element is not necessary for encoding dates or times. In the following snippet, the time is encoded using time
, so that it can be restyled (e.g. using XBL2) to match local conventions, while the year is not marked up at all, since marking it up would not be particularly useful, and doing so is thus not allowed.
<p>I usually have a snack at <time>16:00</time>.</p> <p>I've liked model trains since at least 1983.</p>
Using a styling technology that supports restyling times, the first paragraph from the above snippet could be rendered as follows:
I usually have a snack at 4pm.
Or it could be rendered as follows:
I usually have a snack at 16h00.
The dateTime
IDL attribute must reflect the datetime
content attribute.
The pubDate
IDL attribute must reflect the pubdate
content attribute.
valueAsDate
Returns a Date
object representing the specified date and time.
In the following snippet:
<p>Our first date was <time datetime="2006-09-23">a Saturday</time>.</p>
...the time
element's valueAsDate
attribute would have the value 1,158,969,600,000ms.
In the following snippet:
<p>Many people get up at <time>08:00</time>.</p>
...the time
element's valueAsDate
attribute would have the value 28,800,000ms.
In this example, an article's publication date is marked up using time
:
<article> <h1>Small tasks</h1> <footer>Published <time pubdate>2009-08-30</time>.</footer> <p>I put a bike bell on his bike.</p> </article>
Here is another way that could be marked up. In this example, legacy user agents would say "today", while newer user agents would render the time in a locale-specific manner based on the value of the attribute.
<article> <h1>Small tasks</h1> <footer>Published <time pubdate datetime="2009-08-30">today</time>.</footer> <p>I put a bike bell on his bike.</p> </article>
Here is the same thing but with the time included only. Because the element is empty, legacy user agents will not show anything useful; user agents that implement this specification, on the other hand, would show the date and time in a locale-specific manner.
<article> <h1>Small tasks</h1> <footer>Published <time pubdate datetime="2009-08-30T07:13Z"></time>.</footer> <p>I put a bike bell on his bike.</p> </article>
code
elementHTMLElement
.The code
element represents a fragment of computer code. This could be an XML element name, a filename, a computer program, or any other string that a computer would recognize.
Although there is no formal way to indicate the language of computer code being marked up, authors who wish to mark code
elements with the language used, e.g. so that syntax highlighting scripts can use the right rules, may do so by adding a class prefixed with "language-
" to the element.
The following example shows how the element can be used in a paragraph to mark up element names and computer code, including punctuation.
<p>The <code>code</code> element represents a fragment of computer code.</p> <p>When you call the <code>activate()</code> method on the <code>robotSnowman</code> object, the eyes glow.</p> <p>The example below uses the <code>begin</code> keyword to indicate the start of a statement block. It is paired with an <code>end</code> keyword, which is followed by the <code>.</code> punctuation character (full stop) to indicate the end of the program.</p>
The following example shows how a block of code could be marked up using the pre
and code
elements.
<pre><code class="language-pascal">var i: Integer; begin i := 1; end.</code></pre>
A class is used in that example to indicate the language used.
See the pre
element for more details.
var
elementHTMLElement
.The var
element represents a variable. This could be an actual variable in a mathematical expression or programming context, or it could just be a term used as a placeholder in prose.
In the paragraph below, the letter "n" is being used as a variable in prose:
<p>If there are <var>n</var> pipes leading to the ice cream factory then I expect at <em>least</em> <var>n</var> flavors of ice cream to be available for purchase!</p>
For mathematics, in particular for anything beyond the simplest of expressions, MathML is more appropriate. However, the var
element can still be used to refer to specific variables that are then mentioned in MathML expressions.
In this example, an equation is shown, with a legend that references the variables in the equation. The expression itself is marked up with MathML, but the variables are mentioned in the figure's legend using var
.
<figure> <math> <mi>a</mi> <mo>=</mo> <msqrt> <msup><mi>b</mi><mn>2</mn></msup> <mi>+</mi> <msup><mi>c</mi><mn>2</mn></msup> </msqrt> </math> <figcaption> Using Pythagoras' theorem to solve for the hypotenuse <var>a</var> of a triangle with sides <var>b</var> and <var>c</var> </figcaption> </figure>
samp
elementHTMLElement
.The samp
element represents (sample) output from a program or computing system.
See the pre
and kbd
elements for more details.
This example shows the samp
element being used inline:
<p>The computer said <samp>Too much cheese in tray two</samp> but I didn't know what that meant.</p>
This second example shows a block of sample output. Nested samp
and kbd
elements allow for the styling of specific elements of the sample output using a style sheet.
<pre><samp><span class="prompt">jdoe@mowmow:~$</span> <kbd>ssh demo.example.com</kbd> Last login: Tue Apr 12 09:10:17 2005 from mowmow.example.com on pts/1 Linux demo 2.6.10-grsec+gg3+e+fhs6b+nfs+gr0501+++p3+c4a+gr2b-reslog-v6.189 #1 SMP Tue Feb 1 11:22:36 PST 2005 i686 unknown <span class="prompt">jdoe@demo:~$</span> <span class="cursor">_</span></samp></pre>
kbd
elementHTMLElement
.The kbd
element represents user input (typically keyboard input, although it may also be used to represent other input, such as voice commands).
When the kbd
element is nested inside a samp
element, it represents the input as it was echoed by the system.
When the kbd
element contains a samp
element, it represents input based on system output, for example invoking a menu item.
When the kbd
element is nested inside another kbd
element, it represents an actual key or other single unit of input as appropriate for the input mechanism.
Here the kbd
element is used to indicate keys to press:
<p>To make George eat an apple, press <kbd><kbd>Shift</kbd>+<kbd>F3</kbd></kbd></p>
In this second example, the user is told to pick a particular menu item. The outer kbd
element marks up a block of input, with the inner kbd
elements representing each individual step of the input, and the samp
elements inside them indicating that the steps are input based on something being displayed by the system, in this case menu labels:
<p>To make George eat an apple, select <kbd><kbd><samp>File</samp></kbd>|<kbd><samp>Eat Apple...</samp></kbd></kbd> </p>
Such precision isn't necessary; the following is equally fine:
<p>To make George eat an apple, select <kbd>File | Eat Apple...</kbd></p>
sub
and sup
elementsHTMLElement
.The sup
element represents a superscript and the sub
element represents a subscript.
These elements must be used only to mark up typographical conventions with specific meanings, not for typographical presentation for presentation's sake. For example, it would be inappropriate for the sub
and sup
elements to be used in the name of the LaTeX document preparation system. In general, authors should use these elements only if the absence of those elements would change the meaning of the content.
In certain languages, superscripts are part of the typographical conventions for some abbreviations.
<p>The most beautiful women are <span lang="fr"><abbr>M<sup>lle</sup></abbr> Gwendoline</span> and <span lang="fr"><abbr>M<sup>me</sup></abbr> Denise</span>.</p>
The sub
element can be used inside a var
element, for variables that have subscripts.
Here, the sub
element is used to represents the subscript that identifies the variable in a family of variables:
<p>The coordinate of the <var>i</var>th point is (<var>x<sub><var>i</var></sub></var>, <var>y<sub><var>i</var></sub></var>). For example, the 10th point has coordinate (<var>x<sub>10</sub></var>, <var>y<sub>10</sub></var>).</p>
Mathematical expressions often use subscripts and superscripts. Authors are encouraged to use MathML for marking up mathematics, but authors may opt to use sub
and sup
if detailed mathematical markup is not desired. [MATHML]
<var>E</var>=<var>m</var><var>c</var><sup>2</sup>
f(<var>x</var>, <var>n</var>) = log<sub>4</sub><var>x</var><sup><var>n</var></sup>
i
elementHTMLElement
.The i
element represents a span of text in an alternate voice or mood, or otherwise offset from the normal prose in a manner indicating a different quality of text, such as a taxonomic designation, a technical term, an idiomatic phrase from another language, a thought, or a ship name in Western texts.
Terms in languages different from the main text should be annotated with lang
attributes (or, in XML, lang
attributes in the XML namespace).
The examples below show uses of the i
element:
<p>The <i class="taxonomy">Felis silvestris catus</i> is cute.</p> <p>The term <i>prose content</i> is defined above.</p> <p>There is a certain <i lang="fr">je ne sais quoi</i> in the air.</p>
In the following example, a dream sequence is marked up using i
elements.
<p>Raymond tried to sleep.</p> <p><i>The ship sailed away on Thursday</i>, he dreamt. <i>The ship had many people aboard, including a beautiful princess called Carey. He watched her, day-in, day-out, hoping she would notice him, but she never did.</i></p> <p><i>Finally one night he picked up the courage to speak with her—</i></p> <p>Raymond woke with a start as the fire alarm rang out.</p>
Authors can use the class
attribute on the i
element to identify why the element is being used, so that if the style of a particular use (e.g. dream sequences as opposed to taxonomic terms) is to be changed at a later date, the author doesn't have to go through the entire document (or series of related documents) annotating each use.
Authors are encouraged to consider whether other elements might be more applicable than the i
element, for instance the em
element for marking up stress emphasis, or the dfn
element to mark up the defining instance of a term.
Style sheets can be used to format i
elements, just like any other element can be restyled. Thus, it is not the case that content in i
elements will necessarily be italicized.
b
elementHTMLElement
.The b
element represents a span of text to which attention is being drawn for utilitarian purposes without conveying any extra importance and with no implication of an alternate voice or mood, such as key words in a document abstract, product names in a review, actionable words in interactive text-driven software, or an article lede.
The following example shows a use of the b
element to highlight key words without marking them up as important:
<p>The <b>frobonitor</b> and <b>barbinator</b> components are fried.</p>
In the following example, objects in a text adventure are highlighted as being special by use of the b
element.
<p>You enter a small room. Your <b>sword</b> glows brighter. A <b>rat</b> scurries past the corner wall.</p>
Another case where the b
element is appropriate is in marking up the lede (or lead) sentence or paragraph. The following example shows how a BBC article about kittens adopting a rabbit as their own could be marked up:
<article> <h2>Kittens 'adopted' by pet rabbit</h2> <p><b class="lede">Six abandoned kittens have found an unexpected new mother figure — a pet rabbit.</b></p> <p>Veterinary nurse Melanie Humble took the three-week-old kittens to her Aberdeen home.</p> [...]
As with the i
element, authors can use the class
attribute on the b
element to identify why the element is being used, so that if the style of a particular use is to be changed at a later date, the author doesn't have to go through annotating each use.
The b
element should be used as a last resort when no other element is more appropriate. In particular, headings should use the h1
to h6
elements, stress emphasis should use the em
element, importance should be denoted with the strong
element, and text marked or highlighted should use the mark
element.
The following would be incorrect usage:
<p><b>WARNING!</b> Do not frob the barbinator!</p>
In the previous example, the correct element to use would have been strong
, not b
.
Style sheets can be used to format b
elements, just like any other element can be restyled. Thus, it is not the case that content in b
elements will necessarily be boldened.
u
elementHTMLElement
.The u
element represents a span of text with an unarticulated, though explicitly rendered, non-textual annotation, such as labeling the text as being a proper name in Chinese text (a Chinese proper name mark), or labeling the text as being misspelt.
In most cases, another element is likely to be more appropriate: for marking stress emphasis, the em
element should be used; for marking key words or phrases either the b
element or the mark
element should be used, depending on the context; for marking book titles, the cite
element should be used; for labeling text with explicit textual annotations, the ruby
element should be used; for labeling ship names in Western texts, the i
element should be used.
The default rendering of the u
element in visual presentations clashes with the conventional rendering of hyperlinks (underlining). Authors are encouraged to avoid using the u
element where it could be confused for a hyperlink.
mark
elementHTMLElement
.The mark
element represents a run of text in one document marked or highlighted for reference purposes, due to its relevance in another context. When used in a quotation or other block of text referred to from the prose, it indicates a highlight that was not originally present but which has been added to bring the reader's attention to a part of the text that might not have been considered important by the original author when the block was originally written, but which is now under previously unexpected scrutiny. When used in the main prose of a document, it indicates a part of the document that has been highlighted due to its likely relevance to the user's current activity.
This example shows how the mark
element can be used to bring attention to a particular part of a quotation:
<p lang="en-US">Consider the following quote:</p> <blockquote lang="en-GB"> <p>Look around and you will find, no-one's really <mark>colour</mark> blind.</p> </blockquote> <p lang="en-US">As we can tell from the <em>spelling</em> of the word, the person writing this quote is clearly not American.</p>
(If the goal was to mark the element as misspelt, however, the u
element, possibly with a class, would be more appropriate.
Another example of the mark
element is highlighting parts of a document that are matching some search string. If someone looked at a document, and the server knew that the user was searching for the word "kitten", then the server might return the document with one paragraph modified as follows:
<p>I also have some <mark>kitten</mark>s who are visiting me these days. They're really cute. I think they like my garden! Maybe I should adopt a <mark>kitten</mark>.</p>
In the following snippet, a paragraph of text refers to a specific part of a code fragment.
<p>The highlighted part below is where the error lies:</p> <pre><code>var i: Integer; begin i := <mark>1.1</mark>; end.</code></pre>
This is separate from syntax highlighting, for which span
is more appropriate. Combining both, one would get:
<p>The highlighted part below is where the error lies:</p> <pre><code><span class=keyword>var</span> <span class=ident>i</span>: <span class=type>Integer</span>; <span class=keyword>begin</span> <span class=ident>i</span> := <span class=literal><mark>1.1</mark></span>; <span class=keyword>end</span>.</code></pre>
This is another example showing the use of mark
to highlight a part of quoted text that was originally not emphasized. In this example, common typographic conventions have led the author to explicitly style mark
elements in quotes to render in italics.
<article> <style scoped> blockquote mark, q mark { font: inherit; font-style: italic; text-decoration: none; background: transparent; color: inherit; } .bubble em { font: inherit; font-size: larger; text-decoration: underline; } </style> <h1>She knew</h1> <p>Did you notice the subtle joke in the joke on panel 4?</p> <blockquote> <p class="bubble">I didn't <em>want</em> to believe. <mark>Of course on some level I realized it was a known-plaintext attack.</mark> But I couldn't admit it until I saw for myself.</p> </blockquote> <p>(Emphasis mine.) I thought that was great. It's so pedantic, yet it explains everything neatly.</p> </article>
Note, incidentally, the distinction between the em
element in this example, which is part of the original text being quoted, and the mark
element, which is highlighting a part for comment.
The following example shows the difference between denoting the importance of a span of text (strong
) as opposed to denoting the relevance of a span of text (mark
). It is an extract from a textbook, where the extract has had the parts relevant to the exam highlighted. The safety warnings, important though they may be, are apparently not relevant to the exam.
<h3>Wormhole Physics Introduction</h3> <p><mark>A wormhole in normal conditions can be held open for a maximum of just under 39 minutes.</mark> Conditions that can increase the time include a powerful energy source coupled to one or both of the gates connecting the wormhole, and a large gravity well (such as a black hole).</p> <p><mark>Momentum is preserved across the wormhole. Electromagnetic radiation can travel in both directions through a wormhole, but matter cannot.</mark></p> <p>When a wormhole is created, a vortex normally forms. <strong>Warning: The vortex caused by the wormhole opening will annihilate anything in its path.</strong> Vortexes can be avoided when using sufficiently advanced dialing technology.</p> <p><mark>An obstruction in a gate will prevent it from accepting a wormhole connection.</mark></p>
ruby
elementrt
element, or an rp
element, an rt
element, and another rp
element.HTMLElement
.The ruby
element allows one or more spans of phrasing content to be marked with ruby annotations. Ruby annotations are short runs of text presented alongside base text, primarily used in East Asian typography as a guide for pronunciation or to include other annotations. In Japanese, this form of typography is also known as furigana.
A ruby
element represents the spans of phrasing content it contains, ignoring all the child rt
and rp
elements and their descendants. Those spans of phrasing content have associated annotations created using the rt
element.
In this example, each ideograph in the Japanese text 漢字 is annotated with its reading in hiragana.
...
<ruby>漢<rt>かん</rt>字<rt>じ </rt></ruby>
...
This might be rendered as:
In this example, each ideograph in the traditional Chinese text 漢字 is annotated with its bopomofo reading.
<ruby>漢<rt>ㄏㄢˋ</rt>字<rt>ㄗˋ </rt></ruby>
This might be rendered as:
In this example, each ideograph in the simplified Chinese text 汉字 is annotated with its pinyin reading.
...<ruby>汉<rt>hàn</rt>字<rt>zì </rt></ruby>...
This might be rendered as:
rt
elementruby
element.HTMLElement
.The rt
element marks the ruby text component of a ruby annotation.
An rt
element represents an annotation (given by its children) for the zero or more nodes of phrasing content that immediately precedes it in the ruby
element, ignoring rp
elements.
rp
elementruby
element, either immediately before or immediately after an rt
element.HTMLElement
.The rp
element can be used to provide parentheses around a ruby text component of a ruby annotation, to be shown by user agents that don't support ruby annotations.
An rp
element represents nothing.
The example above, in which each ideograph in the text 漢字 is annotated with its phonetic reading, could be expanded to use rp
so that in legacy user agents the readings are in parentheses:
...
<ruby>
漢 <rp>(</rp><rt>かん</rt><rp>)</rp>
字 <rp>(</rp><rt>じ</rt><rp>)</rp>
</ruby>
...
In conforming user agents the rendering would be as above, but in user agents that do not support ruby, the rendering would be:
... 漢 (かん) 字 (じ) ...
bdi
elementdir
global attribute has special semantics on this element.HTMLElement
.The bdi
element represents a span of text that is to be isolated from its surroundings for the purposes of bidirectional text formatting. [BIDI]
The dir
global attribute defaults to auto
on this element (it never inherits from the parent element like with other elements).
This element is especially useful when embedding user-generated content with an unknown directionality.
In this example, usernames are shown along with the number of posts that the user has submitted. If the bdi
element were not used, the username of the Arabic user would end up confusing the text (the bidirectional algorithm would put the colon and the number "3" next to the word "User" rather than next to the word "posts").
<ul> <li>User <bdi>jcranmer</bdi>: 12 posts. <li>User <bdi>hober</bdi>: 5 posts. <li>User <bdi>إيان</bdi>: 3 posts. </ul>
bdo
elementdir
global attribute has special semantics on this element.HTMLElement
.The bdo
element represents explicit text directionality formatting control for its children. It allows authors to override the Unicode bidirectional algorithm by explicitly specifying a direction override. [BIDI]
Authors must specify the dir
attribute on this element, with the value ltr
to specify a left-to-right override and with the value rtl
to specify a right-to-left override.
span
elementinterface HTMLSpanElement : HTMLElement {};
The span
element doesn't mean anything on its own, but can be useful when used together with the global attributes, e.g. class
, lang
, or dir
. It represents its children.
In this example, a code fragment is marked up using span
elements and class
attributes so that its keywords and identifiers can be color-coded from CSS:
<pre><code class="lang-c"><span class="keyword">for</span> (<span class="ident">j</span> = 0; <span class="ident">j</span> < 256; <span class="ident">j</span>++) { <span class="ident">i_t3</span> = (<span class="ident">i_t3</span> & 0x1ffff) | (<span class="ident">j</span> << 17); <span class="ident">i_t6</span> = (((((((<span class="ident">i_t3</span> >> 3) ^ <span class="ident">i_t3</span>) >> 1) ^ <span class="ident">i_t3</span>) >> 8) ^ <span class="ident">i_t3</span>) >> 5) & 0xff; <span class="keyword">if</span> (<span class="ident">i_t6</span> == <span class="ident">i_t1</span>) <span class="keyword">break</span>; }</code></pre>
br
elementinterface HTMLBRElement : HTMLElement {};
The br
element represents a line break.
While line breaks are usually represented in visual media by physically moving subsequent text to a new line, a style sheet or user agent would be equally justified in causing line breaks to be rendered in a different manner, for instance as green dots, or as extra spacing.
br
elements must be used only for line breaks that are actually part of the content, as in poems or addresses.
The following example is correct usage of the br
element:
<p>P. Sherman<br> 42 Wallaby Way<br> Sydney</p>
br
elements must not be used for separating thematic groups in a paragraph.
The following examples are non-conforming, as they abuse the br
element:
<p><a ...>34 comments.</a><br> <a ...>Add a comment.</a></p>
<p><label>Name: <input name="name"></label><br> <label>Address: <input name="address"></label></p>
Here are alternatives to the above, which are correct:
<p><a ...>34 comments.</a></p> <p><a ...>Add a comment.</a></p>
<p><label>Name: <input name="name"></label></p> <p><label>Address: <input name="address"></label></p>
If a paragraph consists of nothing but a single br
element, it represents a placeholder blank line (e.g. as in a template). Such blank lines must not be used for presentation purposes.
wbr
elementHTMLElement
.The wbr
element represents a line break opportunity.
In the following example, someone is quoted as saying something which, for effect, is written as one long word. However, to ensure that the text can be wrapped in a readable fashion, the individual words in the quote are separated using a wbr
element.
<p>So then he pointed at the tiger and screamed "there<wbr>is<wbr>no<wbr>way<wbr>you<wbr>are<wbr>ever<wbr>going<wbr>to<wbr>catch<wbr>me"!</p>
Element | Purpose | Example |
---|---|---|
a |
Hyperlinks |
Visit my <a href="drinks.html">drinks</a> page. |
em |
Stress emphasis |
I must say I <em>adore</em> lemonade. |
strong |
Importance |
This tea is <strong>very hot</strong>. |
small |
Side comments |
These grapes are made into wine. <small>Alcohol is addictive.</small> |
s |
Inaccurate text |
Price: <s>£4.50</s> £2.00! |
cite |
Titles of works |
The case <cite>Hugo v. Danielle</cite> is relevant here. |
q |
Quotations |
The judge said <q>You can drink water from the fish tank</q> but advised against it. |
dfn |
Defining instance |
The term <dfn>organic food</dfn> refers to food produced without synthetic chemicals. |
abbr |
Abbreviations |
Organic food in Ireland is certified by the <abbr title="Irish Organic Farmers and Growers Association">IOFGA</abbr>. |
time |
Date and/or time |
Published <time>2009-10-21</time>. |
code |
Computer code |
The <code>fruitdb</code> program can be used for tracking fruit production. |
var |
Variables |
If there are <var>n</var> fruit in the bowl, at least <var>n</var>÷2 will be ripe. |
samp |
Computer output |
The computer said <samp>Unknown error -3</samp>. |
kbd |
User input |
Hit <kbd>F1</kbd> to continue. |
sub |
Subscripts |
Water is H<sub>2</sub>O. |
sup |
Superscripts |
The Hydrogen in heavy water is usually <sup>2</sup>H. |
i |
Alternative voice |
Lemonade consists primarily of <i>Citrus limon</i>. |
b |
Keywords |
Take a <b>lemon</b> and squeeze it with a <b>juicer</b>. |
u |
Annotations |
The mixture of apple juice and <u class="spelling">eldeflower</u> juice is very pleasant. |
mark |
Highlight |
Elderflower cordial, with one <mark>part</mark> cordial to ten <mark>part</mark>s water, stands a<mark>part</mark> from the rest. |
ruby , rt , rp |
Ruby annotations |
<ruby> OJ <rp>(<rt>Orange Juice<rp>)</ruby> |
bdi |
Text directionality isolation |
The recommended restaurant is <bdi lang="">My Juice Café (At The Beach)</bdi>. |
bdo |
Text directionality formatting |
The proposal is to write English, but in reverse order. "Juice" would become "<bdo dir=rtl>Juice</bdo>" |
span |
Other |
In French we call it <span lang="fr">sirop de sureau</span>. |
br |
Line break |
Simply Orange Juice Company<br>Apopka, FL 32703<br>U.S.A. |
wbr |
Line breaking opportunity |
www.simply<wbr>orange<wbr>juice.com |
The ins
and del
elements represent edits to the document.
ins
elementcite
datetime
HTMLModElement
interface.The ins
element represents an addition to the document.
The following represents the addition of a single paragraph:
<aside> <ins> <p> I like fruit. </p> </ins> </aside>
As does this, because everything in the aside
element here counts as phrasing content and therefore there is just one paragraph:
<aside> <ins> Apples are <em>tasty</em>. </ins> <ins> So are pears. </ins> </aside>
ins
elements should not cross implied paragraph boundaries.
The following example represents the addition of two paragraphs, the second of which was inserted in two parts. The first ins
element in this example thus crosses a paragraph boundary, which is considered poor form.
<aside> <!-- don't do this --> <ins datetime="2005-03-16T00:00Z"> <p> I like fruit. </p> Apples are <em>tasty</em>. </ins> <ins datetime="2007-12-19T00:00Z"> So are pears. </ins> </aside>
Here is a better way of marking this up. It uses more elements, but none of the elements cross implied paragraph boundaries.
<aside> <ins datetime="2005-03-16T00:00Z"> <p> I like fruit. </p> </ins> <ins datetime="2005-03-16T00:00Z"> Apples are <em>tasty</em>. </ins> <ins datetime="2007-12-19T00:00Z"> So are pears. </ins> </aside>
del
elementcite
datetime
HTMLModElement
interface.The del
element represents a removal from the document.
del
elements should not cross implied paragraph boundaries.
The following shows a "to do" list where items that have been done are crossed-off with the date and time of their completion.
<h1>To Do</h1> <ul> <li>Empty the dishwasher</li> <li><del datetime="2009-10-11T01:25-07:00">Watch Walter Lewin's lectures</del></li> <li><del datetime="2009-10-10T23:38-07:00">Download more tracks</del></li> <li>Buy a printer</li> </ul>
ins
and del
elementsThe cite
attribute may be used to specify the address of a document that explains the change. When that document is long, for instance the minutes of a meeting, authors are encouraged to include a fragment identifier pointing to the specific part of that document that discusses the change.
If the cite
attribute is present, it must be a valid URL potentially surrounded by spaces that explains the change.
The datetime
attribute may be used to specify the time and date of the change.
If present, the datetime
attribute's value must be a valid date string with optional time.
The ins
and del
elements implement the HTMLModElement
interface:
interface HTMLModElement : HTMLElement { attribute DOMString cite; attribute DOMString dateTime; };
The cite
IDL attribute must reflect the element's cite
content attribute. The dateTime
IDL attribute must reflect the element's datetime
content attribute.
Since the ins
and del
elements do not affect paragraphing, it is possible, in some cases where paragraphs are implied (without explicit p
elements), for an ins
or del
element to span both an entire paragraph or other non-phrasing content elements and part of another paragraph. For example:
<section> <ins> <p> This is a paragraph that was inserted. </p> This is another paragraph whose first sentence was inserted at the same time as the paragraph above. </ins> This is a second sentence, which was there all along. </section>
By only wrapping some paragraphs in p
elements, one can even get the end of one paragraph, a whole second paragraph, and the start of a third paragraph to be covered by the same ins
or del
element (though this is very confusing, and not considered good practice):
<section> This is the first paragraph. <ins>This sentence was inserted. <p>This second paragraph was inserted.</p> This sentence was inserted too.</ins> This is the third paragraph in this example. <!-- (don't do this) --> </section>
However, due to the way implied paragraphs are defined, it is not possible to mark up the end of one paragraph and the start of the very next one using the same ins
or del
element. You instead have to use one (or two) p
element(s) and two ins
or del
elements, as for example:
<section> <p>This is the first paragraph. <del>This sentence was deleted.</del></p> <p><del>This sentence was deleted too.</del> That sentence needed a separate <del> element.</p> </section>
Partly because of the confusion described above, authors are strongly encouraged to always mark up all paragraphs with the p
element, instead of having ins
or del
elements that cross implied paragraphs boundaries.
The content models of the ol
and ul
elements do not allow ins
and del
elements as children. Lists always represent all their items, including items that would otherwise have been marked as deleted.
To indicate that an item is inserted or deleted, an ins
or del
element can be wrapped around the contents of the li
element. To indicate that an item has been replaced by another, a single li
element can have one or more del
elements followed by one or more ins
elements.
In the following example, a list that started empty had items added and removed from it over time. The bits in the example that have been emphasized show the parts that are the "current" state of the list. The list item numbers don't take into account the edits, though.
<h1>Stop-ship bugs</h1> <ol> <li><ins datetime="2008-02-12T15:20Z">Bug 225: Rain detector doesn't work in snow</ins></li> <li><del datetime="2008-03-01T20:22Z"><ins datetime="2008-02-14T12:02Z">Bug 228: Water buffer overflows in April</ins></del></li> <li><ins datetime="2008-02-16T13:50Z">Bug 230: Water heater doesn't use renewable fuels</ins></li> <li><del datetime="2008-02-20T21:15Z"><ins datetime="2008-02-16T14:25Z">Bug 232: Carbon dioxide emissions detected after startup</ins></del></li> </ol>
In the following example, a list that started with just fruit was replaced by a list with just colors.
<h1>List of <del>fruits</del><ins>colors</ins></h1> <ul> <li><del>Lime</del><ins>Green</ins></li> <li><del>Apple</del></li> <li>Orange</li> <li><del>Pear</del></li> <li><ins>Teal</ins></li> <li><del>Lemon</del><ins>Yellow</ins></li> <li>Olive</li> <li><ins>Purple</ins></li> </ul>
The img, iframe, embed, object, param, video, audio, source, track, canvas, map, and area elements.
img
elementISSUE-30 (longdesc) impacts this section. Priority feedback is requested on this issue from Last Call reviewers. In particular, reviewers are invited to review and comment on any change proposals that are related to this issue. See the current list of open Last Call issues and change proposals maintained by the HTML Working Group chairs.
usemap
attribute: Interactive content.alt
src
usemap
ismap
width
height
[NamedConstructor=Image(), NamedConstructor=Image(in unsigned long width), NamedConstructor=Image(in unsigned long width, in unsigned long height)] interface HTMLImageElement : HTMLElement { attribute DOMString alt; attribute DOMString src; attribute DOMString useMap; attribute boolean isMap; attribute unsigned long width; attribute unsigned long height; readonly attribute unsigned long naturalWidth; readonly attribute unsigned long naturalHeight; readonly attribute boolean complete; };
An img
element represents an image.
The image given by the src
attribute is the embedded content; the value of the alt
attribute provides equivalent content for those who cannot process images or who have image loading disabled.
The src
attribute must be present, and must contain a valid non-empty URL potentially surrounded by spaces referencing a non-interactive, optionally animated, image resource that is neither paged nor scripted.
Images can thus be static bitmaps (e.g. PNGs, GIFs, JPEGs), single-page vector documents (single-page PDFs, XML files with an SVG root element), animated bitmaps (APNGs, animated GIFs), animated vector graphics (XML files with an SVG root element that use declarative SMIL animation), and so forth. However, this also precludes SVG files with script, multipage PDF files, interactive MNG files, HTML documents, plain text documents, and so forth.
The requirements on the alt
attribute's value are described in the next section.
The img
element must not be used as a layout tool. In particular, img
elements should not be used to display transparent images, as they rarely convey meaning and rarely add anything useful to the document.
The usemap
attribute, if present, can indicate that the image has an associated image map.
The ismap
attribute, when used on an element that is a descendant of an a
element with an href
attribute, indicates by its presence that the element provides access to a server-side image map. This affects how events are handled on the corresponding a
element.
The ismap
attribute is a boolean attribute. The attribute must not be specified on an element that does not have an ancestor a
element with an href
attribute.
The img
element supports dimension attributes.
The IDL attributes alt
, src
, useMap
, and isMap
each must reflect the respective content attributes of the same name.
width
[ = value ]height
[ = value ]These attributes return the actual rendered dimensions of the image, or zero if the dimensions are not known.
They can be set, to change the corresponding content attributes.
naturalWidth
naturalHeight
These attributes return the intrinsic dimensions of the image, or zero if the dimensions are not known.
complete
Returns true if the image has been completely downloaded or if no image is specified; otherwise, returns false.
Image
( [ width [, height ] ] )Returns a new img
element, with the width
and height
attributes set to the values passed in the relevant arguments, if applicable.
On setting, they must act as if they reflected the respective content attributes of the same name.
Three constructors are provided for creating HTMLImageElement
objects (in addition to the factory methods from DOM Core such as createElement()
): Image()
, Image(width)
, and Image(width, height)
. When invoked as constructors, these must return a new HTMLImageElement
object (a new img
element). If the width argument is present, the new object's width
content attribute must be set to width. If the height argument is also present, the new object's height
content attribute must be set to height. The element's document must be the active document of the browsing context of the Window
object on which the interface object of the invoked constructor is found.
A single image can have different appropriate alternative text depending on the context.
In each of the following cases, the same image is used, yet the alt
text is different each time. The image is the coat of arms of the Carouge municipality in the canton Geneva in Switzerland.
Here it is used as a supplementary icon:
<p>I lived in <img src="carouge.svg" alt=""> Carouge.</p>
Here it is used as an icon representing the town:
<p>Home town: <img src="carouge.svg" alt="Carouge"></p>
Here it is used as part of a text on the town:
<p>Carouge has a coat of arms.</p> <p><img src="carouge.svg" alt="The coat of arms depicts a lion, sitting in front of a tree."></p> <p>It is used as decoration all over the town.</p>
Here it is used as a way to support a similar text where the description is given as well as, instead of as an alternative to, the image:
<p>Carouge has a coat of arms.</p> <p><img src="carouge.svg" alt=""></p> <p>The coat of arms depicts a lion, sitting in front of a tree. It is used as decoration all over the town.</p>
Here it is used as part of a story:
<p>He picked up the folder and a piece of paper fell out.</p> <p><img src="carouge.svg" alt="Shaped like a shield, the paper had a red background, a green tree, and a yellow lion with its tongue hanging out and whose tail was shaped like an S."></p> <p>He stared at the folder. S! The answer he had been looking for all this time was simply the letter S! How had he not seen that before? It all came together now. The phone call where Hector had referred to a lion's tail, the time Marco had stuck his tongue out...</p>
Here it is not known at the time of publication what the image will be, only that it will be a coat of arms of some kind, and thus no replacement text can be provided, and instead only a brief caption for the image is provided, in the title
attribute:
<p>The last user to have uploaded a coat of arms uploaded this one:</p> <p><img src="last-uploaded-coat-of-arms.cgi" title="User-uploaded coat of arms."></p>
Ideally, the author would find a way to provide real replacement text even in this case, e.g. by asking the previous user. Not providing replacement text makes the document more difficult to use for people who are unable to view images, e.g. blind users, or users or very low-bandwidth connections or who pay by the byte, or users who are forced to use a text-only Web browser.
Here are some more examples showing the same picture used in different contexts, with different appropriate alternate texts each time.
<article> <h1>My cats</h1> <h2>Fluffy</h2> <p>Fluffy is my favorite.</p> <img src="fluffy.jpg" alt="She likes playing with a ball of yarn."> <p>She's just too cute.</p> <h2>Miles</h2> <p>My other cat, Miles just eats and sleeps.</p> </article>
<article> <h1>Photography</h1> <h2>Shooting moving targets indoors</h2> <p>The trick here is to know how to anticipate; to know at what speed and what distance the subject will pass by.</p> <img src="fluffy.jpg" alt="A cat flying by, chasing a ball of yarn, can be photographed quite nicely using this technique."> <h2>Nature by night</h2> <p>To achieve this, you'll need either an extremely sensitive film, or immense flash lights.</p> </article>
<article> <h1>About me</h1> <h2>My pets</h2> <p>I've got a cat named Fluffy and a dog named Miles.</p> <img src="fluffy.jpg" alt="Fluffy, my cat, tends to keep itself busy."> <p>My dog Miles and I like go on long walks together.</p> <h2>music</h2> <p>After our walks, having emptied my mind, I like listening to Bach.</p> </article>
<article> <h1>Fluffy and the Yarn</h1> <p>Fluffy was a cat who liked to play with yarn. He also liked to jump.</p> <aside><img src="fluffy.jpg" alt="" title="Fluffy"></aside> <p>He would play in the morning, he would play in the evening.</p> </article>
Except where otherwise specified, the alt
attribute must be specified and its value must not be empty; the value must be an appropriate replacement for the image. The specific requirements for the alt
attribute depend on what the image is intended to represent, as described in the following sections.
The most general rule to consider when writing alternative text is the following: the intent is that replacing every image with the text of its alt
attribute not change the meaning of the page.
So, in general, alternative text can be written by considering what one would have written had one not been able to include the image.
A corollary to this is that the alt
attribute's value should never contain text that could be considered the image's caption, title, or legend. It is supposed to contain replacement text that could be used by users instead of the image; it is not meant to supplement the image. The title
attribute can be used for supplemental information.
One way to think of alternative text is to think about how you would read the page containing the image to someone over the phone, without mentioning that there is an image present. Whatever you say instead of the image is typically a good start for writing the alternative text.
When an a element that creates a hyperlink, or a button
element, has no textual content but contains one or more images, the alt
attributes must contain text that together convey the purpose of the link or button.
In this example, a user is asked to pick his preferred color from a list of three. Each color is given by an image, but for users who have configured their user agent not to display images, the color names are used instead:
<h1>Pick your color</h1> <ul> <li><a href="green.html"><img src="green.jpeg" alt="Green"></a></li> <li><a href="blue.html"><img src="blue.jpeg" alt="Blue"></a></li> <li><a href="red.html"><img src="red.jpeg" alt="Red"></a></li> </ul>
In this example, each button has a set of images to indicate the kind of color output desired by the user. The first image is used in each case to give the alternative text.
<button name="rgb"><img src="red" alt="RGB"><img src="green" alt=""><img src="blue" alt=""></button> <button name="cmyk"><img src="cyan" alt="CMYK"><img src="magenta" alt=""><img src="yellow" alt=""><img src="black" alt=""></button>
Since each image represents one part of the text, it could also be written like this:
<button name="rgb"><img src="red" alt="R"><img src="green" alt="G"><img src="blue" alt="B"></button> <button name="cmyk"><img src="cyan" alt="C"><img src="magenta" alt="M"><img src="yellow" alt="Y"><img src="black" alt="K"></button>
However, with other alternative text, this might not work, and putting all the alternative text into one image in each case might make more sense:
<button name="rgb"><img src="red" alt="sRGB profile"><img src="green" alt=""><img src="blue" alt=""></button> <button name="cmyk"><img src="cyan" alt="CMYK profile"><img src="magenta" alt=""><img src="yellow" alt=""><img src="black" alt=""></button>
Sometimes something can be more clearly stated in graphical form, for example as a flowchart, a diagram, a graph, or a simple map showing directions. In such cases, an image can be given using the img
element, but the lesser textual version must still be given, so that users who are unable to view the image (e.g. because they have a very slow connection, or because they are using a text-only browser, or because they are listening to the page being read out by a hands-free automobile voice Web browser, or simply because they are blind) are still able to understand the message being conveyed.
The text must be given in the alt
attribute, and must convey the same message as the image specified in the src
attribute.
It is important to realize that the alternative text is a replacement for the image, not a description of the image.
In the following example we have a flowchart in image form, with text in the alt
attribute rephrasing the flowchart in prose form:
<p>In the common case, the data handled by the tokenization stage comes from the network, but it can also come from script.</p> <p><img src="parsing-model-overview.png" alt="The network passes data to the Tokenizer stage, which passes data to the Tree Construction stage. From there, data goes to both the DOM and to Script Execution. Script Execution is linked to the DOM, and, using document.write(), passes data to the Tokenizer."></p>
Here's another example, showing a good solution and a bad solution to the problem of including an image in a description.
First, here's the good solution. This sample shows how the alternative text should just be what you would have put in the prose if the image had never existed.
<!-- This is the correct way to do things. --> <p> You are standing in an open field west of a house. <img src="house.jpeg" alt="The house is white, with a boarded front door."> There is a small mailbox here. </p>
Second, here's the bad solution. In this incorrect way of doing things, the alternative text is simply a description of the image, instead of a textual replacement for the image. It's bad because when the image isn't shown, the text doesn't flow as well as in the first example.
<!-- This is the wrong way to do things. --> <p> You are standing in an open field west of a house. <img src="house.jpeg" alt="A white house, with a boarded front door."> There is a small mailbox here. </p>
Text such as "Photo of white house with boarded door" would be equally bad alternative text (though it could be suitable for the title
attribute or in the figcaption
element of a figure
with this image).
A document can contain information in iconic form. The icon is intended to help users of visual browsers to recognize features at a glance.
In some cases, the icon is supplemental to a text label conveying the same meaning. In those cases, the alt
attribute must be present but must be empty.
Here the icons are next to text that conveys the same meaning, so they have an empty alt
attribute:
<nav> <p><a href="/help/"><img src="/icons/help.png" alt=""> Help</a></p> <p><a href="/configure/"><img src="/icons/configuration.png" alt=""> Configuration Tools</a></p> </nav>
In other cases, the icon has no text next to it describing what it means; the icon is supposed to be self-explanatory. In those cases, an equivalent textual label must be given in the alt
attribute.
Here, posts on a news site are labeled with an icon indicating their topic.
<body> <article> <header> <h1>Ratatouille wins <i>Best Movie of the Year</i> award</h1> <p><img src="movies.png" alt="Movies"></p> </header> <p>Pixar has won yet another <i>Best Movie of the Year</i> award, making this its 8th win in the last 12 years.</p> </article> <article> <header> <h1>Latest TWiT episode is online</h1> <p><img src="podcasts.png" alt="Podcasts"></p> </header> <p>The latest TWiT episode has been posted, in which we hear several tech news stories as well as learning much more about the iPhone. This week, the panelists compare how reflective their iPhones' Apple logos are.</p> </article> </body>
Many pages include logos, insignia, flags, or emblems, which stand for a particular entity such as a company, organization, project, band, software package, country, or some such.
If the logo is being used to represent the entity, e.g. as a page heading, the alt
attribute must contain the name of the entity being represented by the logo. The alt
attribute must not contain text like the word "logo", as it is not the fact that it is a logo that is being conveyed, it's the entity itself.
If the logo is being used next to the name of the entity that it represents, then the logo is supplemental, and its alt
attribute must instead be empty.
If the logo is merely used as decorative material (as branding, or, for example, as a side image in an article that mentions the entity to which the logo belongs), then the entry below on purely decorative images applies. If the logo is actually being discussed, then it is being used as a phrase or paragraph (the description of the logo) with an alternative graphical representation (the logo itself), and the first entry above applies.
In the following snippets, all four of the above cases are present. First, we see a logo used to represent a company:
<h1><img src="XYZ.gif" alt="The XYZ company"></h1>
Next, we see a paragraph which uses a logo right next to the company name, and so doesn't have any alternative text:
<article> <h2>News</h2> <p>We have recently been looking at buying the <img src="alpha.gif" alt=""> ΑΒΓ company, a small Greek company specializing in our type of product.</p>
In this third snippet, we have a logo being used in an aside, as part of the larger article discussing the acquisition:
<aside><p><img src="alpha-large.gif" alt=""></p></aside> <p>The ΑΒΓ company has had a good quarter, and our pie chart studies of their accounts suggest a much bigger blue slice than its green and orange slices, which is always a good sign.</p> </article>
Finally, we have an opinion piece talking about a logo, and the logo is therefore described in detail in the alternative text.
<p>Consider for a moment their logo:</p> <p><img src="/images/logo" alt="It consists of a green circle with a green question mark centered inside it."></p> <p>How unoriginal can you get? I mean, oooooh, a question mark, how <em>revolutionary</em>, how utterly <em>ground-breaking</em>, I'm sure everyone will rush to adopt those specifications now! They could at least have tried for some sort of, I don't know, sequence of rounded squares with varying shades of green and bold white outlines, at least that would look good on the cover of a blue book.</p>
This example shows how the alternative text should be written such that if the image isn't available, and the text is used instead, the text flows seamlessly into the surrounding text, as if the image had never been there in the first place.
Sometimes, an image just consists of text, and the purpose of the image is not to highlight the actual typographic effects used to render the text, but just to convey the text itself.
In such cases, the alt
attribute must be present but must consist of the same text as written in the image itself.
Consider a graphic containing the text "Earth Day", but with the letters all decorated with flowers and plants. If the text is merely being used as a heading, to spice up the page for graphical users, then the correct alternative text is just the same text "Earth Day", and no mention need be made of the decorations:
<h1><img src="earthdayheading.png" alt="Earth Day"></h1>
In many cases, the image is actually just supplementary, and its presence merely reinforces the surrounding text. In these cases, the alt
attribute must be present but its value must be the empty string.
In general, an image falls into this category if removing the image doesn't make the page any less useful, but including the image makes it a lot easier for users of visual browsers to understand the concept.
A flowchart that repeats the previous paragraph in graphical form:
<p>The network passes data to the Tokenizer stage, which passes data to the Tree Construction stage. From there, data goes to both the DOM and to Script Execution. Script Execution is linked to the DOM, and, using document.write(), passes data to the Tokenizer.</p> <p><img src="parsing-model-overview.png" alt=""></p>
In these cases, it would be wrong to include alternative text that consists of just a caption. If a caption is to be included, then either the title
attribute can be used, or the figure
and figcaption
elements can be used. In the latter case, the image would in fact be a phrase or paragraph with an alternative graphical representation, and would thus require alternative text.
<!-- Using the title="" attribute --> <p>The network passes data to the Tokenizer stage, which passes data to the Tree Construction stage. From there, data goes to both the DOM and to Script Execution. Script Execution is linked to the DOM, and, using document.write(), passes data to the Tokenizer.</p> <p><img src="parsing-model-overview.png" alt="" title="Flowchart representation of the parsing model."></p>
<!-- Using <figure> and <figcaption> --> <p>The network passes data to the Tokenizer stage, which passes data to the Tree Construction stage. From there, data goes to both the DOM and to Script Execution. Script Execution is linked to the DOM, and, using document.write(), passes data to the Tokenizer.</p> <figure> <img src="parsing-model-overview.png" alt="The Network leads to the Tokenizer, which leads to the Tree Construction. The Tree Construction leads to two items. The first is Script Execution, which leads via document.write() back to the Tokenizer. The second item from which Tree Construction leads is the DOM. The DOM is related to the Script Execution."> <figcaption>Flowchart representation of the parsing model.</figcaption> </figure>
<!-- This is WRONG. Do not do this. Instead, do what the above examples do. --> <p>The network passes data to the Tokenizer stage, which passes data to the Tree Construction stage. From there, data goes to both the DOM and to Script Execution. Script Execution is linked to the DOM, and, using document.write(), passes data to the Tokenizer.</p> <p><img src="parsing-model-overview.png" alt="Flowchart representation of the parsing model."></p> <!-- Never put the image's caption in the alt="" attribute! -->
A graph that repeats the previous paragraph in graphical form:
<p>According to a study covering several billion pages, about 62% of documents on the Web in 2007 triggered the Quirks rendering mode of Web browsers, about 30% triggered the Almost Standards mode, and about 9% triggered the Standards mode.</p> <p><img src="rendering-mode-pie-chart.png" alt=""></p>
If an image is decorative but isn't especially page-specific — for example an image that forms part of a site-wide design scheme — the image should be specified in the site's CSS, not in the markup of the document.
Exceptions to this rule, in cases where CSS cannot be used to display an entirely decorative image, are covered by the HTML5: Techniques for providing useful text alternatives. [HTMLALTTECHS] Authors are also encouraged to consult the Web Content Accessibility Guidelines 2.0 for more detailed information and acceptable techniques. [WCAG]
When a picture has been sliced into smaller image files that are then displayed together to form the complete picture again, one of the images must have its alt
attribute set as per the relevant rules that would be appropriate for the picture as a whole, and then all the remaining images must have their alt
attribute set to the empty string.
In the following example, a picture representing a company logo for XYZ Corp has been split into two pieces, the first containing the letters "XYZ" and the second with the word "Corp". The alternative text ("XYZ Corp") is all in the first image.
<h1><img src="logo1.png" alt="XYZ Corp"><img src="logo2.png" alt=""></h1>
In the following example, a rating is shown as three filled stars and two empty stars. While the alternative text could have been "★★★☆☆", the author has instead decided to more helpfully give the rating in the form "3 out of 5". That is the alternative text of the first image, and the rest have blank alternative text.
<p>Rating: <meter max=5 value=3><img src="1" alt="3 out of 5" ><img src="1" alt=""><img src="1" alt=""><img src="0" alt="" ><img src="0" alt=""></meter></p>
Generally, image maps should be used instead of slicing an image for links.
However, if an image is indeed sliced and any of the components of the sliced picture are the sole contents of links, then one image per link must have alternative text in its alt
attribute representing the purpose of the link.
In the following example, a picture representing the flying spaghetti monster emblem, with each of the left noodly appendages and the right noodly appendages in different images, so that the user can pick the left side or the right side in an adventure.
<h1>The Church</h1> <p>You come across a flying spaghetti monster. Which side of His Noodliness do you wish to reach out for?</p> <p><a href="?go=left" ><img src="fsm-left.png" alt="Left side. "></a ><img src="fsm-middle.png" alt="" ><a href="?go=right"><img src="fsm-right.png" alt="Right side."></a></p>
In some cases, the image is a critical part of the content. This could be the case, for instance, on a page that is part of a photo gallery. The image is the whole point of the page containing it.
How to provide alternative text for an image that is a key part of the content depends on the image's provenance.
When it is possible for detailed alternative text to be provided, for example if the image is part of a series of screenshots in a magazine review, or part of a comic strip, or is a photograph in a blog entry about that photograph, text that can serve as a substitute for the image must be given as the contents of the alt
attribute.
A screenshot in a gallery of screenshots for a new OS, with some alternative text:
<figure> <img src="KDE%20Light%20desktop.png" alt="The desktop is blue, with icons along the left hand side in two columns, reading System, Home, K-Mail, etc. A window is open showing that menus wrap to a second line if they cannot fit in the window. The window has a list of icons along the top, with an address bar below it, a list of icons for tabs along the left edge, a status bar on the bottom, and two panes in the middle. The desktop has a bar at the bottom of the screen with a few buttons, a pager, a list of open applications, and a clock."> <figcaption>Screenshot of a KDE desktop.</figcaption> </figure>
A graph in a financial report:
<img src="sales.gif" title="Sales graph" alt="From 1998 to 2005, sales increased by the following percentages with each year: 624%, 75%, 138%, 40%, 35%, 9%, 21%">
Note that "sales graph" would be inadequate alternative text for a sales graph. Text that would be a good caption is not generally suitable as replacement text.
In certain cases, the nature of the image might be such that providing thorough alternative text is impractical. For example, the image could be indistinct, or could be a complex fractal, or could be a detailed topographical map.
In these cases, the alt
attribute must contain some suitable alternative text, but it may be somewhat brief.
Sometimes there simply is no text that can do justice to an image. For example, there is little that can be said to usefully describe a Rorschach inkblot test. However, a description, even if brief, is still better than nothing:
<figure> <img src="/commons/a/a7/Rorschach1.jpg" alt="A shape with left-right symmetry with indistinct edges, with a small gap in the center, two larger gaps offset slightly from the center, with two similar gaps under them. The outline is wider in the top half than the bottom half, with the sides extending upwards higher than the center, and the center extending below the sides."> <figcaption>A black outline of the first of the ten cards in the Rorschach inkblot test.</figcaption> </figure>
Note that the following would be a very bad use of alternative text:
<!-- This example is wrong. Do not copy it. --> <figure> <img src="/commons/a/a7/Rorschach1.jpg" alt="A black outline of the first of the ten cards in the Rorschach inkblot test."> <figcaption>A black outline of the first of the ten cards in the Rorschach inkblot test.</figcaption> </figure>
Including the caption in the alternative text like this isn't useful because it effectively duplicates the caption for users who don't have images, taunting them twice yet not helping them any more than if they had only read or heard the caption once.
Another example of an image that defies full description is a fractal, which, by definition, is infinite in detail.
The following example shows one possible way of providing alternative text for the full view of an image of the Mandelbrot set.
<img src="ms1.jpeg" alt="The Mandelbrot set appears as a cardioid with its cusp on the real axis in the positive direction, with a smaller bulb aligned along the same center line, touching it in the negative direction, and with these two shapes being surrounded by smaller bulbs of various sizes.">
In some unfortunate cases, there might be no alternative text available at all, either because the image is obtained in some automated fashion without any associated alternative text (e.g. a Webcam), or because the page is being generated by a script using user-provided images where the user did not provide suitable or usable alternative text (e.g. photograph sharing sites), or because the author does not himself know what the images represent (e.g. a blind photographer sharing an image on his blog).
In such cases, the alt
attribute may be omitted, but one of the following conditions must be met as well:
title
attribute is present and has a non-empty value.img
element is in a figure
element that contains a figcaption
element that contains content other than inter-element whitespace, and, ignoring the figcaption
element and its descendants, the figure
element has no text node descendants other than inter-element whitespace, and no embedded content descendant other than the img
element.Such cases are to be kept to an absolute minimum. If there is even the slightest possibility of the author having the ability to provide real alternative text, then it would not be acceptable to omit the alt
attribute.
A photo on a photo-sharing site, if the site received the image with no metadata other than the caption, could be marked up as follows:
<figure> <img src="1100670787_6a7c664aef.jpg"> <figcaption>Bubbles traveled everywhere with us.</figcaption> </figure>
It would be better, however, if a detailed description of the important parts of the image obtained from the user and included on the page.
A blind user's blog in which a photo taken by the user is shown. Initially, the user might not have any idea what the photo he took shows:
<article> <h1>I took a photo</h1> <p>I went out today and took a photo!</p> <figure> <img src="photo2.jpeg"> <figcaption>A photograph taken blindly from my front porch.</figcaption> </figure> </article>
Eventually though, the user might obtain a description of the image from his friends and could then include alternative text:
<article> <h1>I took a photo</h1> <p>I went out today and took a photo!</p> <figure> <img src="photo2.jpeg" alt="The photograph shows my hummingbird feeder hanging from the edge of my roof. It is half full, but there are no birds around. In the background, out-of-focus trees fill the shot. The feeder is made of wood with a metal grate, and it contains peanuts. The edge of the roof is wooden too, and is painted white with light blue streaks."> <figcaption>A photograph taken blindly from my front porch.</figcaption> </figure> </article>
Sometimes the entire point of the image is that a textual description is not available, and the user is to provide the description. For instance, the point of a CAPTCHA image is to see if the user can literally read the graphic. Here is one way to mark up a CAPTCHA (note the title
attribute):
<p><label>What does this image say? <img src="captcha.cgi?id=8934" title="CAPTCHA"> <input type=text name=captcha></label> (If you cannot see the image, you can use an <a href="?audio">audio</a> test instead.)</p>
Another example would be software that displays images and asks for alternative text precisely for the purpose of then writing a page with correct alternative text. Such a page could have a table of images, like this:
<table> <thead> <tr> <th> Image <th> Description <tbody> <tr> <td> <img src="2421.png" title="Image 640 by 100, filename 'banner.gif'"> <td> <input name="alt2421"> <tr> <td> <img src="2422.png" title="Image 200 by 480, filename 'ad3.gif'"> <td> <input name="alt2422"> </table>
Notice that even in this example, as much useful information as possible is still included in the title
attribute.
Since some users cannot use images at all (e.g. because they have a very slow connection, or because they are using a text-only browser, or because they are listening to the page being read out by a hands-free automobile voice Web browser, or simply because they are blind), the alt
attribute is only allowed to be omitted rather than being provided with replacement text when no alternative text is available and none can be made available, as in the above examples. Lack of effort from the part of the author is not an acceptable reason for omitting the alt
attribute.
Generally authors should avoid using img
elements for purposes other than showing images.
If an img
element is being used for purposes other than showing an image, e.g. as part of a service to count page views, then the alt
attribute must be the empty string.
In such cases, the width
and height
attributes should both be set to zero.
iframe
elementsrc
srcdoc
name
sandbox
seamless
width
height
interface HTMLIFrameElement : HTMLElement { attribute DOMString src; attribute DOMString srcdoc; attribute DOMString name; [PutForwards=value] readonly attribute DOMSettableTokenList sandbox; attribute boolean seamless; attribute DOMString width; attribute DOMString height; readonly attribute Document contentDocument; readonly attribute WindowProxy contentWindow; };
The iframe
element represents a nested browsing context.
The src
attribute gives the address of a page that the nested browsing context is to contain. The attribute, if present, must be a valid non-empty URL potentially surrounded by spaces.
The srcdoc
attribute gives the content of the page that the nested browsing context is to contain. The value of the attribute is the source of an iframe
srcdoc
document.
For iframe
elements in HTML documents, the attribute, if present, must have a value using the HTML syntax that consists of the following syntactic components, in the given order:
html
element.For iframe
elements in XML documents, the attribute, if present, must have a value that matches the production labeled document
in the XML specification. [XML]
If the src
attribute and the srcdoc
attribute are both specified together, the srcdoc
attribute takes priority. This allows authors to provide a fallback URL for legacy user agents that do not support the srcdoc
attribute.
If, when the element is created, the srcdoc
attribute is not set, and the src
attribute is either also not set or set but its value cannot be resolved, the browsing context will remain at the initial about:blank
page.
If the user navigates away from this page, the iframe
's corresponding WindowProxy
object will proxy new Window
objects for new Document
objects, but the src
attribute will not change.
Here a blog uses the srcdoc
attribute in conjunction with the sandbox
and seamless
attributes described below to provide users of user agents that support this feature with an extra layer of protection from script injection in the blog post comments:
<article> <h1>I got my own magazine!</h1> <p>After much effort, I've finally found a publisher, and so now I have my own magazine! Isn't that awesome?! The first issue will come out in September, and we have articles about getting food, and about getting in boxes, it's going to be great!</p> <footer> <p>Written by <a href="/users/cap">cap</a>. <time pubdate>2009-08-21T23:32Z</time></p> </footer> <article> <footer> At <time pubdate>2009-08-21T23:35Z</time>, <a href="/users/ch">ch</a> writes: </footer> <iframe seamless sandbox srcdoc="<p>did you get a cover picture yet?"></iframe> </article> <article> <footer> At <time pubdate>2009-08-21T23:44Z</time>, <a href="/users/cap">cap</a> writes: </footer> <iframe seamless sandbox srcdoc="<p>Yeah, you can see it <a href="/gallery?mode=cover&amp;page=1">in my gallery</a>."></iframe> </article> <article> <footer> At <time pubdate>2009-08-21T23:58Z</time>, <a href="/users/ch">ch</a> writes: </footer> <iframe seamless sandbox srcdoc="<p>hey that's earl's table. <p>you should get earl&amp;me on the next cover."></iframe> </article>
Notice the way that quotes have to be escaped (otherwise the sandbox
attribute would end prematurely), and the way raw ampersands (e.g. in URLs or in prose) mentioned in the sandboxed content have to be doubly escaped — once so that the ampersand is preserved when originally parsing the sandbox
attribute, and once more to prevent the ampersand from being misinterpreted when parsing the sandboxed content.
In the HTML syntax, authors need only remember to use U+0022 QUOTATION MARK characters (") to wrap the attribute contents and then to escape all U+0022 QUOTATION MARK (") and U+0026 AMPERSAND (&) characters, and to specify the sandbox
attribute, to ensure safe embedding of content.
Due to restrictions of the XML syntax, in XML the U+003C LESS-THAN SIGN character (<) needs to be escaped as well. In order to prevent attribute-value normalization, some of XML's whitespace characters — specifically U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), and U+000D CARRIAGE RETURN (CR) — also need to be escaped. [XML]
The name
attribute, if present, must be a valid browsing context name. The given value is used to name the nested browsing context.
The sandbox
attribute, when specified, enables a set of extra restrictions on any content hosted by the iframe
. Its value must be an unordered set of unique space-separated tokens that are ASCII case-insensitive. The allowed values are allow-same-origin
, allow-top-navigation
, allow-forms
, and allow-scripts
. When the attribute is set, the content is treated as being from a unique origin, forms and scripts are disabled, links are prevented from targeting other
browsing contexts, and plugins are disabled. The allow-same-origin
keyword allows the content to be treated as being from the same origin instead of forcing it into a unique origin, the allow-top-navigation
keyword allows the content to navigate its top-level browsing context, and the allow-forms
and allow-scripts
keywords re-enable forms and scripts respectively (though scripts are still prevented from creating popups).
Setting both the allow-scripts
and allow-same-origin
keywords together when the embedded page has the same origin as the page containing the iframe
allows the embedded page to simply remove
the sandbox
attribute.
Sandboxing hostile content is of minimal help if an attacker can convince the user to just visit the hostile content directly, rather than in the iframe
. To limit the damage that can be caused by hostile HTML content, it should be served using the text/html-sandboxed
MIME type.
In this example, some completely-unknown, potentially hostile, user-provided HTML content is embedded in a page. Because it is sandboxed, it is treated by the user agent as being from a unique origin, despite the content being served from the same site. Thus it is affected by all the normal cross-site restrictions. In addition, the embedded page has scripting disabled, plugins disabled, forms disabled, and it cannot navigate any frames or windows other than itself (or any frames or windows it itself embeds).
<p>We're not scared of you! Here is your content, unedited:</p> <iframe sandbox src="getusercontent.cgi?id=12193"></iframe>
Note that cookies are still sent to the server in the getusercontent.cgi
request, though they are not visible in the document.cookie
IDL attribute.
It is important that the server serve the user-provided HTML using the text/html-sandboxed
MIME type so that if the attacker convinces the user to visit that page directly, the page doesn't run in the context of the site's origin, which would make the user vulnerable to any attack found in the page.
In this example, a gadget from another site is embedded. The gadget has scripting and forms enabled, and the origin sandbox restrictions are lifted, allowing the gadget to communicate with its originating server. The sandbox is still useful, however, as it disables plugins and popups, thus reducing the risk of the user being exposed to malware and other annoyances.
<iframe sandbox="allow-same-origin allow-forms allow-scripts" src="http://maps.example.com/embedded.html"></iframe>
Suppose a file A contained the following fragment:
<iframe sandbox="allow-same-origin allow-forms" src=B></iframe>
Suppose that file B contained an iframe also:
<iframe sandbox="allow-scripts" src=C></iframe>
Further, suppose that file C contained a link:
<a href=D>Link</a>
For this example, suppose all the files were served as text/html
.
Page C in this scenario has all the sandboxing flags set. Scripts are disabled, because the iframe
in A has scripts disabled, and this overrides the allow-scripts
keyword set on the iframe
in B. Forms are also disabled, because the inner iframe
(in B) does not have the allow-forms
keyword set.
Suppose now that a script in A removes all the sandbox
attributes in A and B. This would change nothing immediately. If the user clicked the link in C, loading page D into the iframe
in B, page D would now act as if the iframe
in B had the allow-same-origin
and allow-forms
keywords set, because that was the state of the nested browsing context in the iframe
in A when page B was loaded.
Generally speaking, dynamically removing or changing the sandbox
attribute is ill-advised, because it can make it quite hard to reason about what will be allowed and what will not.
Potentially hostile files can be served from the same server as the file containing the iframe
element by labeling them as text/html-sandboxed
instead of text/html
. This ensures that scripts in the files are unable to attack the site (as if they were actually served from another server), even if the user is tricked into visiting those pages directly, without the protection of the sandbox
attribute.
If the allow-scripts
keyword is set along with allow-same-origin
keyword, and the file is from the same origin as the iframe
's Document
,
then a script in the "sandboxed" iframe could just reach out, remove the sandbox
attribute, and then reload itself, effectively breaking out of the sandbox altogether.
The seamless
attribute is a boolean attribute. When specified, it indicates that the iframe
element's browsing context is to be rendered in a manner that makes it appear to be part of the containing document (seamlessly included in the parent document).
The attribute can be set or removed dynamically, with the rendering updating in tandem.
In this example, the site's navigation is embedded using a client-side include using an iframe
. Any links in the iframe
will, in new user agents, be automatically opened in the iframe
's parent browsing context; for legacy user agents, the site could also include a base
element with a target
attribute with the value _parent
. Similarly, in new user agents the styles of the parent page will be automatically applied to the contents of the frame, but to support legacy user agents authors might wish to include the styles explicitly.
<nav><iframe seamless src="nav.include.html"></iframe></nav>
The iframe
element supports dimension attributes for cases where the embedded content has specific dimensions (e.g. ad units have well-defined dimensions).
An iframe
element never has fallback content, as it will always create a nested browsing context, regardless of whether the specified initial contents are successfully used.
Descendants of iframe
elements represent nothing. (In legacy user agents that do not support iframe
elements, the contents would be parsed as markup that could act as fallback content.)
When used in HTML documents, the allowed content model of iframe
elements is text, except that invoking the HTML fragment parsing algorithm with the iframe
element as the context element and the text contents as the input must result in a list of nodes that are all phrasing content, with no parse errors having occurred, with no script
elements being anywhere in the list or as descendants of elements in the list, and with all the elements in the list (including their descendants) being themselves conforming.
The iframe
element must be empty in XML documents.
The HTML parser treats markup inside iframe
elements as text.
The IDL attributes src
, srcdoc
, name
, sandbox
, and seamless
must reflect the respective content attributes of the same name.
The contentDocument
IDL attribute must return the Document
object of the active document of the iframe
element's nested browsing context.
The contentWindow
IDL attribute must return the WindowProxy
object of the iframe
element's nested browsing context.
Here is an example of a page using an iframe
to include advertising from an advertising broker:
<iframe src="http://ads.example.com/?customerid=923513721&format=banner" width="468" height="60"></iframe>
embed
elementsrc
type
width
height
interface HTMLEmbedElement : HTMLElement { attribute DOMString src; attribute DOMString type; attribute DOMString width; attribute DOMString height; };
The embed
element represents an integration point for an external (typically non-HTML) application or interactive content.
The src
attribute gives the address of the resource being embedded. The attribute, if present, must contain a valid non-empty URL potentially surrounded by spaces.
The type
attribute, if present, gives the MIME type by which the plugin to instantiate is selected. The value must be a valid MIME type. If both the type
attribute and the src
attribute are present, then the type
attribute must specify the same type as the explicit Content-Type metadata of the resource given by the src
attribute.
Any namespace-less attribute other than name
, align
, hspace
, and vspace
may be specified on the embed
element, so long as its name is XML-compatible and contains no characters in the range U+0041 to U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z). These attributes are then passed as parameters to the plugin.
All attributes in HTML documents get lowercased automatically, so the restriction on uppercase letters doesn't affect such documents.
The four exceptions are to exclude legacy attributes that have side-effects beyond just sending parameters to the plugin.
The embed
element supports dimension attributes.
The IDL attributes src
and type
each must reflect the respective content attributes of the same name.
Here's a way to embed a resource that requires a proprietary plug-in, like Flash:
<embed src="catgame.swf">
If the user does not have the plug-in (for example if the plug-in vendor doesn't support the user's platform), then the user will be unable to use the resource.
To pass the plugin a parameter "quality" with the value "high", an attribute can be specified:
<embed src="catgame.swf" quality="high">
This would be equivalent to the following, when using an object
element instead:
<object data="catgame.swf"> <param name="quality" value="high"> </object>
object
elementusemap
attribute: Interactive content.param
elements, then, transparent.data
type
name
usemap
form
width
height
interface HTMLObjectElement : HTMLElement { attribute DOMString data; attribute DOMString type; attribute DOMString name; attribute DOMString useMap; readonly attribute HTMLFormElement form; attribute DOMString width; attribute DOMString height; readonly attribute Document contentDocument; readonly attribute WindowProxy contentWindow; readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); };
The object
element can represent an external resource, which, depending on the type of the resource, will either be treated as an image, as a nested browsing context, or as an external resource to be processed by a plugin.
The data
attribute, if present, specifies the address of the resource. If present, the attribute must be a valid non-empty URL potentially surrounded by spaces.
The type
attribute, if present, specifies the type of the resource. If present, the attribute must be a valid MIME type.
At least one of either the data
attribute or the type
attribute must be present.
The name
attribute, if present, must be a valid browsing context name. The given value is used to name the nested browsing context, if applicable.
The usemap
attribute, if present while the object
element represents an image, can indicate that the object has an associated image map.
The form
attribute is used to explicitly associate the object
element with its form owner.
The object
element supports dimension attributes.
The IDL attributes data
, type
, name
, and useMap
each must reflect the respective content attributes of the same name.
The contentDocument
IDL attribute must return the Document
object of the active document of the object
element's nested browsing context, if it has one; otherwise, it must return null.
The contentWindow
IDL attribute must return the WindowProxy
object of the object
element's nested browsing context, if it has one; otherwise, it must return null.
In the following example, a Java applet is embedded in a page using the object
element. (Generally speaking, it is better to avoid using applets like these and instead use native JavaScript and HTML to provide the functionality, since that way the application will work on all Web browsers without requiring a third-party plugin. Many devices, especially embedded devices, do not support third-party technologies like Java.)
<figure> <object type="application/x-java-applet"> <param name="code" value="MyJavaClass"> <p>You do not have Java available, or it is disabled.</p> </object> <figcaption>My Java Clock</figcaption> </figure>
In this example, an HTML page is embedded in another using the object
element.
<figure> <object data="clock.html"></object> <figcaption>My HTML Clock</figcaption> </figure>
The following example shows how a plugin can be used in HTML (in this case the Flash plugin, to show a video file). Fallback is provided for users who do not have Flash enabled, in this case using the video
element to show the video for those using user agents that support video
, and finally providing a link to the video for those who have neither Flash nor a video
-capable browser.
<p>Look at my video: <object type="application/x-shockwave-flash"> <param name=movie value="http://video.example.com/library/watch.swf"> <param name=allowfullscreen value=true> <param name=flashvars value="http://video.example.com/vids/315981"> <video controls src="http://video.example.com/vids/315981"> <a href="http://video.example.com/vids/315981">View video</a>. </video> </object> </p>
param
elementobject
element, before any flow content.name
value
interface HTMLParamElement : HTMLElement { attribute DOMString name; attribute DOMString value; };
The param
element defines parameters for plugins invoked by object
elements. It does not represent anything on its own.
The name
attribute gives the name of the parameter.
The value
attribute gives the value of the parameter.
Both attributes must be present. They may have any value.
The IDL attributes name
and value
must both reflect the respective content attributes of the same name.
The following example shows how the param
element can be used to pass a parameter to a plugin, in this case the O3D plugin.
<!DOCTYPE HTML> <html lang="en"> <head> <title>O3D Utah Teapot</title> </head> <body> <p> <object type="application/vnd.o3d.auto"> <param name="o3d_features" value="FloatingPointTextures"> <img src="o3d-teapot.png" title="3D Utah Teapot illustration rendered using O3D." alt="When O3D renders the Utah Teapot, it appears as a squat teapot with a shiny metallic finish on which the surroundings are reflected, with a faint shadow caused by the lighting."> <p>To see the teapot actually rendered by O3D on your computer, please download and install the <a href="http://code.google.com/apis/o3d/docs/gettingstarted.html#install">O3D plugin</a>.</p> </object> <script src="o3d-teapot.js"></script> </p> </body> </html>
video
elementcontrols
attribute: Interactive content.src
attribute: zero or more track
elements, then transparent, but with no media element descendants.src
attribute: zero or more source
elements, then zero or more track
elements, then transparent, but with no media element descendants.src
poster
preload
autoplay
mediagroup
loop
muted
controls
width
height
interface HTMLVideoElement : HTMLMediaElement { attribute unsigned long width; attribute unsigned long height; readonly attribute unsigned long videoWidth; readonly attribute unsigned long videoHeight; attribute DOMString poster; };
A video
element is used for playing videos or movies, and audio files with captions.
Content may be provided inside the video
element; it is intended for older Web browsers which do not support video
, so that legacy video plugins can be tried, or to show text to the users of these older browsers informing them of how to access the video contents.
In particular, this content is not intended to address accessibility concerns. To make video content accessible to the blind, deaf, and those with other physical or cognitive disabilities, authors are expected to provide alternative media streams and/or to embed accessibility aids (such as caption or subtitle tracks, audio description tracks, or sign-language overlays) into their media streams.
The video
element is a media element whose media data is ostensibly video data, possibly with associated audio data.
The src
, preload
, autoplay
, mediagroup
, loop
, muted
, and controls
attributes are the attributes common to all media elements.
The poster
attribute gives the address of an image file that the user agent can show while no video data is available. The attribute, if present, must contain a valid non-empty URL potentially surrounded by spaces.
The image given by the poster
attribute, the poster frame, is intended to be a representative frame of the video (typically one of the first non-blank frames) that gives the user an idea of what the video is like.
videoWidth
videoHeight
These attributes return the intrinsic dimensions of the video, or zero if the dimensions are not known.
The video
element supports dimension attributes.
The poster
IDL attribute must reflect the poster
content attribute.
This example shows how to detect when a video has failed to play correctly:
<script> function failed(e) { // video playback failed - show a message saying why switch (e.target.error.code) { case e.target.error.MEDIA_ERR_ABORTED: alert('You aborted the video playback.'); break; case e.target.error.MEDIA_ERR_NETWORK: alert('A network error caused the video download to fail part-way.'); break; case e.target.error.MEDIA_ERR_DECODE: alert('The video playback was aborted due to a corruption problem or because the video used features your browser did not support.'); break; case e.target.error.MEDIA_ERR_SRC_NOT_SUPPORTED: alert('The video could not be loaded, either because the server or network failed or because the format is not supported.'); break; default: alert('An unknown error occurred.'); break; } } </script> <p><video src="tgif.vid" autoplay controls onerror="failed(event)"></video></p> <p><a href="tgif.vid">Download the video file</a>.</p>
audio
elementcontrols
attribute: Interactive content.src
attribute: zero or more track
elements, then transparent, but with no media element descendants.src
attribute: one or more source
elements, then zero or more track
elements, then transparent, but with no media element descendants.src
preload
autoplay
mediagroup
loop
muted
controls
[NamedConstructor=Audio(), NamedConstructor=Audio(in DOMString src)] interface HTMLAudioElement : HTMLMediaElement {};
An audio
element represents a sound or audio stream.
Content may be provided inside the audio
element; it is intended for older Web browsers which do not support audio
, so that legacy audio plugins can be tried, or to show text to the users of these older browsers informing them of how to access the audio contents.
In particular, this content is not intended to address accessibility concerns. To make audio content accessible to the deaf or to those with other physical or cognitive disabilities, authors are expected to provide alternative media streams and/or to embed accessibility aids (such as transcriptions) into their media streams.
The audio
element is a media element whose media data is ostensibly audio data.
The src
, preload
, autoplay
, mediagroup
, loop
, muted
, and controls
attributes are the attributes common to all media elements.
Audio
( [ url ] )Returns a new audio
element, with the src
attribute set to the value passed in the argument, if applicable.
source
elementtrack
elements.src
type
media
interface HTMLSourceElement : HTMLElement { attribute DOMString src; attribute DOMString type; attribute DOMString media; };
The source
element allows authors to specify multiple alternative media resources for media elements. It does not represent anything on its own.
The src
attribute gives the address of the media resource. The value must be a valid non-empty URL potentially surrounded by spaces. This attribute must be present.
Dynamically modifying a source
element and its attribute when the element is already inserted in a video
or audio
element will have no effect. To change what is playing, either just use the src
attribute on the media element directly, or call the load()
method on the media element after manipulating the source
elements.
The type
attribute gives the type of the media resource, to help the user agent determine if it can play this media resource before fetching it. If specified, its value must be a valid MIME type. The codecs
parameter, which certain MIME types define, might be necessary to specify exactly how the resource is encoded. [RFC4281]
The following list shows some examples of how to use the codecs=
MIME parameter in the type
attribute.
<source src='video.mp4' type='video/mp4; codecs="avc1.42E01E, mp4a.40.2"'>
<source src='video.mp4' type='video/mp4; codecs="avc1.58A01E, mp4a.40.2"'>
<source src='video.mp4' type='video/mp4; codecs="avc1.4D401E, mp4a.40.2"'>
<source src='video.mp4' type='video/mp4; codecs="avc1.64001E, mp4a.40.2"'>
<source src='video.mp4' type='video/mp4; codecs="mp4v.20.8, mp4a.40.2"'>
<source src='video.mp4' type='video/mp4; codecs="mp4v.20.240, mp4a.40.2"'>
<source src='video.3gp' type='video/3gpp; codecs="mp4v.20.8, samr"'>
<source src='video.ogv' type='video/ogg; codecs="theora, vorbis"'>
<source src='video.ogv' type='video/ogg; codecs="theora, speex"'>
<source src='audio.ogg' type='audio/ogg; codecs=vorbis'>
<source src='audio.spx' type='audio/ogg; codecs=speex'>
<source src='audio.oga' type='audio/ogg; codecs=flac'>
<source src='video.ogv' type='video/ogg; codecs="dirac, vorbis"'>
The media
attribute gives the intended media type of the media resource, to help the user agent determine if this media resource is useful to the user before fetching it. Its value must be a valid media query.
The default, if the media
attribute is omitted, is "all
", meaning that by default the media resource is suitable for all media.
The IDL attributes src
, type
, and media
must reflect the respective content attributes of the same name.
If the author isn't sure if the user agents will all be able to render the media resources provided, the author can listen to the error
event on the last source
element and trigger fallback behavior:
<script> function fallback(video) { // replace <video> with its contents while (video.hasChildNodes()) { if (video.firstChild instanceof HTMLSourceElement) video.removeChild(video.firstChild); else video.parentNode.insertBefore(video.firstChild, video); } video.parentNode.removeChild(video); } </script> <video controls autoplay> <source src='video.mp4' type='video/mp4; codecs="avc1.42E01E, mp4a.40.2"'> <source src='video.ogv' type='video/ogg; codecs="theora, vorbis"' onerror="fallback(parentNode)"> ... </video>
track
elementkind
src
srclang
label
default
interface HTMLTrackElement : HTMLElement { attribute DOMString kind; attribute DOMString src; attribute DOMString srclang; attribute DOMString label; attribute boolean default; readonly attribute TextTrack track; };
The track
element allows authors to specify explicit external timed text tracks for media elements. It does not represent anything on its own.
The kind
attribute is an enumerated attribute. The following table lists the keywords defined for this attribute. The keyword given in the first cell of each row maps to the state given in the second cell.
Keyword | State | Brief description |
---|---|---|
subtitles |
Subtitles | Transcription or translation of the dialogue, suitable for when the sound is available but not understood (e.g. because the user does not understand the language of the media resource's soundtrack). Displayed over the video. |
captions |
Captions | Transcription or translation of the dialogue, sound effects, relevant musical cues, and other relevant audio information, suitable for when the soundtrack is unavailable (e.g. because it is muted or because the user is deaf). Displayed over the video; labeled as appropriate for the hard-of-hearing. |
descriptions |
Descriptions | Textual descriptions of the video component of the media resource, intended for audio synthesis when the visual component is unavailable (e.g. because the user is interacting with the application without a screen while driving, or because the user is blind). Synthesized as separate audio track. |
chapters |
Chapters | Chapter titles, intended to be used for navigating the media resource. Displayed as an interactive list in the user agent's interface. |
metadata |
Metadata | Tracks intended for use from script. Not displayed by the user agent. |
The attribute may be omitted. The missing value default is the subtitles state.
The src
attribute gives the address of the text track data. The value must be a valid non-empty URL potentially surrounded by spaces. This attribute must be present.
The srclang
attribute gives the language of the text track data. The value must be a valid BCP 47 language tag. This attribute must be present if the element's kind
attribute is in the subtitles state. [BCP47]
The label
attribute gives a user-readable title for the track. This title is used by user agents when listing subtitle, caption, and audio description tracks in their user interface.
The value of the label
attribute, if the attribute is present, must not be the empty string. Furthermore, there must not be two track
element children of the same media element whose kind
attributes are in the same state, whose srclang
attributes are both missing or have values that represent the same language, and whose label
attributes are again both missing or both have the same value.
The default
attribute, if specified, indicates that the track is to be enabled if the user's preferences do not indicate that another track would be more appropriate. There must not be more than one track
element with the same parent node with the default
attribute specified.
track
Returns the TextTrack
object corresponding to the text track of the track
element.
The src
, srclang
, label
, and default
IDL attributes must reflect the respective content attributes of the same name. The kind
IDL attribute must reflect the content attribute of the same name, limited to only known values.
This video has subtitles in several languages:
<video src="brave.webm"> <track kind=subtitles src=brave.en.vtt srclang=en label="English"> <track kind=captions src=brave.en.vtt srclang=en label="English for the Hard of Hearing"> <track kind=subtitles src=brave.fr.vtt srclang=fr label="Français"> <track kind=subtitles src=brave.de.vtt srclang=de label="Deutsch"> </video>
Media elements (audio
and video
, in this specification) implement the following interface:
interface HTMLMediaElement : HTMLElement {
// error state
readonly attribute MediaError error;
// network state
attribute DOMString src;
readonly attribute DOMString currentSrc;
const unsigned short NETWORK_EMPTY = 0;
const unsigned short NETWORK_IDLE = 1;
const unsigned short NETWORK_LOADING = 2;
const unsigned short NETWORK_NO_SOURCE = 3;
readonly attribute unsigned short networkState;
attribute DOMString preload;
readonly attribute TimeRanges buffered;
void load();
DOMString canPlayType(in DOMString type);
// ready state
const unsigned short HAVE_NOTHING = 0;
const unsigned short HAVE_METADATA = 1;
const unsigned short HAVE_CURRENT_DATA = 2;
const unsigned short HAVE_FUTURE_DATA = 3;
const unsigned short HAVE_ENOUGH_DATA = 4;
readonly attribute unsigned short readyState;
readonly attribute boolean seeking;
// playback state
attribute double currentTime;
readonly attribute double initialTime;
readonly attribute double duration;
readonly attribute Date startOffsetTime;
readonly attribute boolean paused;
attribute double defaultPlaybackRate;
attribute double playbackRate;
readonly attribute TimeRanges played;
readonly attribute TimeRanges seekable;
readonly attribute boolean ended;
attribute boolean autoplay;
attribute boolean loop;
void play();
void pause();
// media controller
attribute DOMString mediaGroup;
attribute MediaController controller;
// controls
attribute boolean controls;
attribute double volume;
attribute boolean muted;
attribute boolean defaultMuted;
// tracks
readonly attribute MultipleTrackList audioTracks;
readonly attribute ExclusiveTrackList videoTracks;
readonly attribute TextTrack[] textTracks;
MutableTextTrack addTextTrack(in DOMString kind, in optional DOMString label, in optional DOMString language);
};
The media element attributes, src
, preload
, autoplay
, mediagroup
, loop
, muted
, and controls
, apply to all media elements. They are defined in this section.
Media elements are used to present audio data, or video and audio data, to the user. This is referred to as media data in this section, since this section applies equally to media elements for audio or for video. The term media resource is used to refer to the complete set of media data, e.g. the complete video file, or complete audio file.
A media resource can have multiple audio and video tracks. For the purposes of a media element, the video data of the media resource is only that of the currently selected track (if any) given by the element's videoTracks
attribute, and the audio data of the media resource is the result of mixing all the currently enabled tracks (if any) given by the element's audioTracks
attribute.
Both audio
and video
elements can be used for both audio and video. The main difference between the two is simply that the audio
element has no playback area for visual content (such as video or captions), whereas the video
element does.
error
Returns a MediaError
object representing the current error state of the element.
Returns null if there is no error.
interface MediaError { const unsigned short MEDIA_ERR_ABORTED = 1; const unsigned short MEDIA_ERR_NETWORK = 2; const unsigned short MEDIA_ERR_DECODE = 3; const unsigned short MEDIA_ERR_SRC_NOT_SUPPORTED = 4; readonly attribute unsigned short code; };
error
. code
Returns the current error's error code, from the list below.
MEDIA_ERR_ABORTED
(numeric value 1)MEDIA_ERR_NETWORK
(numeric value 2)MEDIA_ERR_DECODE
(numeric value 3)MEDIA_ERR_SRC_NOT_SUPPORTED
(numeric value 4)src
attribute was not suitable.The src
content attribute on media elements gives the address of the media resource (video, audio) to show. The attribute, if present, must contain a valid non-empty URL potentially surrounded by spaces.
The src
IDL attribute on media elements must reflect the content attribute of the same name.
currentSrc
Returns the address of the current media resource.
Returns the empty string when there is no media resource.
There are two ways to specify a media resource, the src
attribute, or source
elements. The attribute overrides the elements.
A media resource can be described in terms of its type, specifically a MIME type, in some cases with a codecs
parameter. (Whether the codecs
parameter is allowed or not depends on the MIME type.) [RFC4281]
Types are usually somewhat incomplete descriptions; for example "video/mpeg
" doesn't say anything except what the container type is, and even a type like "video/mp4; codecs="avc1.42E01E, mp4a.40.2"
" doesn't include information like the actual bitrate (only the maximum bitrate). Thus, given a type, a user agent can often only know whether it might be able to play media of that type (with varying levels of confidence), or whether it definitely cannot play media of that type.
A type that the user agent knows it cannot render is one that describes a resource that the user agent definitely does not support, for example because it doesn't recognize the container type, or it doesn't support the listed codecs.
The MIME type "application/octet-stream
" with no parameters is never a type that the user agent knows it cannot render. User agents must treat that type as equivalent to the lack of any explicit Content-Type metadata when it is used to label a potential media resource.
"application/octet-stream
" is special-cased here; if any parameter appears with it, it should be treated just like any other MIME type. This is a deviation from the rule that unknown MIME type parameters should be ignored.
canPlayType
(type)Returns the empty string (a negative response), "maybe", or "probably" based on how confident the user agent is that it can play media resources of the given type.
This script tests to see if the user agent supports a (fictional) new format to dynamically decide whether to use a video
element or a plugin:
<section id="video"> <p><a href="playing-cats.nfv">Download video</a></p> </section> <script> var videoSection = document.getElementById('video'); var videoElement = document.createElement('video'); var support = videoElement.canPlayType('video/x-new-fictional-format;codecs="kittens,bunnies"'); if (support != "probably" && "New Fictional Video Plug-in" in navigator.plugins) { // not confident of browser support // but we have a plugin // so use plugin instead videoElement = document.createElement("embed"); } else if (support == "") { // no support from browser and no plugin // do nothing videoElement = null; } if (videoElement) { while (videoSection.hasChildNodes()) videoSection.removeChild(videoSection.firstChild); videoElement.setAttribute("src", "playing-cats.nfv"); videoSection.appendChild(videoElement); } </script>
The type
attribute of the source
element allows the user agent to avoid downloading resources that use formats it cannot render.
networkState
Returns the current state of network activity for the element, from the codes in the list below.
NETWORK_EMPTY
(numeric value 0)NETWORK_IDLE
(numeric value 1)NETWORK_LOADING
(numeric value 2)NETWORK_NO_SOURCE
(numeric value 3)load
()Causes the element to reset and start selecting and loading a new media resource from scratch.
The preload
attribute is an enumerated attribute. The following table lists the keywords and states for the attribute — the keywords in the left column map to the states in the cell in the second column on the same row as the keyword.
Keyword | State | Brief description |
---|---|---|
none |
None | Hints to the user agent that either the author does not expect the user to need the media resource, or that the server wants to minimise unnecessary traffic. |
metadata |
Metadata | Hints to the user agent that the author does not expect the user to need the media resource, but that fetching the resource metadata (dimensions, first frame, track list, duration, etc) is reasonable. |
auto |
Automatic | Hints to the user agent that the user agent can put the user's needs first without risk to the server, up to and including optimistically downloading the entire resource. |
The empty string is also a valid keyword, and maps to the Automatic state. The attribute's missing value default is user-agent defined, though the Metadata state is suggested as a compromise between reducing server load and providing an optimal user experience.
The preload
IDL attribute must reflect the content attribute of the same name, limited to only known values.
The autoplay
attribute can override the preload
attribute (since if the media plays, it naturally has to buffer first, regardless of the hint given by the preload
attribute). Including both is not an error, however.
buffered
Returns a TimeRanges
object that represents the ranges of the media resource that the user agent has buffered.
duration
Returns the length of the media resource, in seconds, assuming that the start of the media resource is at time zero.
Returns NaN if the duration isn't available.
Returns Infinity for unbounded streams.
currentTime
[ = value ]Returns the current playback position, in seconds.
Can be set, to seek to the given time.
Will throw an INVALID_STATE_ERR
exception if there is no selected media resource or if there is a current media controller. Will throw an INDEX_SIZE_ERR
exception if the given time is not within the ranges to which the user agent can seek.
initialTime
Returns the initial playback position, that is, time to which the media resource was automatically seeked when it was loaded. Returns zero if the initial playback position is still unknown.
The startOffsetTime
attribute must return a new Date
object representing the current timeline offset.
The loop
attribute is a boolean attribute that, if specified, indicates that the media element is to seek back to the start of the media resource upon reaching the end.
The loop
attribute has no effect while the element has a current media controller.
The loop
IDL attribute must reflect the content attribute of the same name.
readyState
Returns a value that expresses the current state of the element with respect to rendering the current playback position, from the codes in the list below.
HAVE_NOTHING
(numeric value 0)networkState
attribute are set to NETWORK_EMPTY
are always in the HAVE_NOTHING
state.HAVE_METADATA
(numeric value 1)video
element, the dimensions of the video are also available. The API will no longer raise an exception when seeking. No media data is available for the immediate current playback position. The text tracks are ready.HAVE_CURRENT_DATA
(numeric value 2)HAVE_METADATA
state, or there is no more data to obtain in the direction of playback. For example, in video this corresponds to the user agent having data from the current frame, but not the next frame; and to when playback has ended.HAVE_FUTURE_DATA
(numeric value 3)HAVE_METADATA
state. For example, in video this corresponds to the user agent having data for at least the current frame and the next frame. The user agent cannot be in this state if playback has ended, as the current playback position can never advance in this case.HAVE_ENOUGH_DATA
(numeric value 4)HAVE_FUTURE_DATA
state are met, and, in addition, the user agent estimates that data is being fetched at a rate where the current playback position, if it were to advance at the effective playback rate, would not overtake the available data before playback reaches the end of the media resource.It is possible for the ready state of a media element to jump between these states discontinuously. For example, the state of a media element can jump straight from HAVE_METADATA
to HAVE_ENOUGH_DATA
without passing through the HAVE_CURRENT_DATA
and HAVE_FUTURE_DATA
states.
The autoplay
attribute is a boolean attribute. When present, the user agent will automatically begin playback of the media resource as soon as it can do so without stopping.
Authors are urged to use the autoplay
attribute rather than using script to trigger automatic playback, as this allows the user to override the automatic playback when it is not desired, e.g. when using a screen reader. Authors are also encouraged to consider not using the automatic playback behavior at all, and instead to let the user agent wait for the user to start playback explicitly.
The autoplay
IDL attribute must reflect the content attribute of the same name.
paused
Returns true if playback is paused; false otherwise.
ended
Returns true if playback has reached the end of the media resource.
defaultPlaybackRate
[ = value ]Returns the default rate of playback, for when the user is not fast-forwarding or reversing through the media resource.
Can be set, to change the default rate of playback.
The default rate has no direct effect on playback, but if the user switches to a fast-forward mode, when they return to the normal playback mode, it is expected that the rate of playback will be returned to the default rate of playback.
When the element has a current media controller, the defaultPlaybackRate
attribute is ignored and the current media controller's defaultPlaybackRate
is used instead.
playbackRate
[ = value ]Returns the current rate playback, where 1.0 is normal speed.
Can be set, to change the rate of playback.
When the element has a current media controller, the playbackRate
attribute is ignored and the current media controller's playbackRate
is used instead.
played
Returns a TimeRanges
object that represents the ranges of the media resource that the user agent has played.
play
()Sets the paused
attribute to false, loading the media resource and beginning playback if necessary. If the playback had ended, will restart it from the start.
pause
()Sets the paused
attribute to true, loading the media resource if necessary.
seeking
Returns true if the user agent is currently seeking.
seekable
Returns a TimeRanges
object that represents the ranges of the media resource to which it is possible for the user agent to seek.
A media resource can have multiple embedded audio and video tracks. For example, in addition to the primary video and audio tracks, a media resource could have foreign-language dubbed dialogues, director's commentaries, audio descriptions, alternative angles, or sign-language overlays.
audioTracks
Returns a MultipleTrackList
object representing the audio tracks available in the media resource.
videoTracks
Returns an ExclusiveTrackList
object representing the video tracks available in the media resource.
TrackList
objectsThe MultipleTrackList
and ExclusiveTrackList
interfaces, used by the attributes defined in the previous section, are substantially similar. Their common features are defined in the TrackList
interface, from which they both inherit.
interface TrackList { readonly attribute unsigned long length; DOMString getID(in unsigned long index); DOMString getKind(in unsigned long index); DOMString getLabel(in unsigned long index); DOMString getLanguage(in unsigned long index); attribute Function onchange; }; interface MultipleTrackList : TrackList { boolean isEnabled(in unsigned long index); void enable(in unsigned long index); void disable(in unsigned long index); }; interface ExclusiveTrackList : TrackList { readonly attribute unsigned long selectedIndex; void select(in unsigned long index); };
length
Returns the number of tracks in the list.
getID
( index )Returns the ID of the given track. This is the ID that can be used with a fragment identifier if the format supports the Media Fragments URI syntax. [MEDIAFRAG]
getKind
( index )Returns the category the given track falls into. The possible track categories are given below.
getLabel
( index )Returns the label of the given track, if known, or the empty string otherwise.
getLanguage
( index )Returns the language of the given track, if known, or the empty string otherwise.
isEnabled
( index )Returns true if the given track is active, and false otherwise.
enable
( index )Enables the given track.
disable
( index )Disables the given track.
isEnabled
Returns the index of the currently selected track, if any, or −1 otherwise.
select
( index )Selects the given track.
Category | Definition | Applies to... | Examples |
---|---|---|---|
"alternative " |
A possible alternative to the main track, e.g. a different take of a song (audio), or a different angle (video). | Audio and video. | Ogg: "audio/alterate" or "video/alternate". |
"description " |
An audio description of a video track. | Audio only. | Ogg: "audio/audiodesc". |
"main " |
The primary audio or video track. | Audio and video. | Ogg: "audio/main" or "video/main"; WebM: the "FlagDefault" element is set. |
"sign " |
A sign-language interpretation of an audio track. | Video only. | Ogg: "video/sign". |
"translation " |
A translated version of the main track. | Audio only. | Ogg: "audio/dub". |
"" (empty string) | No explicit kind, or the kind given by the track's metadata is not recognised by the user agent. | Audio and video. | Any other track type or track role. |
The audioTracks
and videoTracks
attributes allow scripts to select which track should play, but it is also possible to select specific tracks declaratively, by specifying particular tracks in the fragment identifier of the URL of the media resource. The format of the fragment identifier depends on the MIME type of the media resource. [RFC2046] [RFC3986]
In this example, a video that uses a format that supports the Media Fragments URI fragment identifier syntax is embedded in such a way that the alternative angles labeled "Alternative" are enabled instead of the default video track. [MEDIAFRAG]
<video src="myvideo#track=Alternative"></video>
Each media element can have a MediaController
. A MediaController
is an object that coordinates the playback of multiple media elements, for instance so that a sign-language interpreter track can be overlaid on a video track, with the two being kept in sync.
By default, a media element has no MediaController
. An implicit MediaController
can be assigned using the mediagroup
content attribute. An explicit MediaController
can be assigned directly using the controller
IDL attribute.
Media elements with a MediaController
are said to be slaved to their controller. The MediaController
modifies the playback rate and the playback volume of each of the media elements slaved to it, and ensures that when any of its slaved media elements unexpectedly stall, the others are stopped at the same time.
When a media element is slaved to a MediaController
, its playback rate is fixed to that of the other tracks in the same MediaController
, and any looping is disabled.
[Constructor] interface MediaController { readonly attribute TimeRanges buffered; readonly attribute TimeRanges seekable; readonly attribute double duration; attribute double currentTime; readonly attribute boolean paused; readonly attribute TimeRanges played; void play(); void pause(); attribute double defaultPlaybackRate; attribute double playbackRate; attribute double volume; attribute boolean muted; attribute Function onemptied; attribute Function onloadedmetadata; attribute Function onloadeddata; attribute Function oncanplay; attribute Function oncanplaythrough; attribute Function onplaying; attribute Function onwaiting; attribute Function ondurationchange; attribute Function ontimeupdate; attribute Function onplay; attribute Function onpause; attribute Function onratechange; attribute Function onvolumechange; };
MediaController
()Returns a new MediaController
object.
controller
[ = controller ]Returns the current MediaController
for the media element, if any; returns null otherwise.
Can be set, to set an explicit MediaController
. Doing so removes the mediagroup
attribute, if any.
buffered
Returns a TimeRanges
object that represents the intersection of the time ranges for which the user agent has all relevant media data for all the slaved media elements.
seekable
Returns a TimeRanges
object that represents the intersection of the time ranges into which the user agent can seek for all the slaved media elements.
duration
Returns the difference between the earliest playable moment and the latest playable moment (not considering whether the data in question is actually buffered or directly seekable, but not including time in the future for infinite streams). Will return zero if there is no media.
currentTime
[ = value ]Returns the current playback position, in seconds, as a position between zero time and the current duration
.
Can be set, to seek to the given time.
paused
Returns true if playback is paused; false otherwise. When this attribute is true, any media element slaved to this controller will be stopped.
played
Returns a TimeRanges
object that represents the union of the time ranges in all the slaved media elements that have been played.
play
()Sets the paused
attribute to false.
pause
()Sets the paused
attribute to true.
defaultPlaybackRate
[ = value ]Returns the default rate of playback.
Can be set, to change the default rate of playback.
This default rate has no direct effect on playback, but if the user switches to a fast-forward mode, when they return to the normal playback mode, it is expected that rate of playback (playbackRate
) will be returned to this default rate.
playbackRate
[ = value ]Returns the current rate of playback.
Can be set, to change the rate of playback.
volume
[ = value ]Returns the current playback volume multiplier, as a number in the range 0.0 to 1.0, where 0.0 is the quietest and 1.0 the loudest.
Can be set, to change the volume multiplier.
Throws an INDEX_SIZE_ERR
if the new value is not in the range 0.0 .. 1.0.
muted
[ = value ]Returns true if all audio is muted (regardless of other attributes either on the controller or on any media elements slaved to this controller), and false otherwise.
Can be set, to change whether the audio is muted or not.
The mediagroup
content attribute on media elements can be used to link multiple media elements together by implicitly creating a MediaController
.
The mediaGroup
IDL attribute on media elements must reflect the mediagroup
content attribute.
Multiple media elements referencing the same media resource will share a single network request. This can be used to efficiently play two (video) tracks from the same media resource in two different places on the screen. Used with the mediagroup
attribute, these elements can also be kept synchronised.
In this example, a sign-languge interpreter track from a movie file is overlaid on the primary video track of that same video file using two video
elements, some CSS, and an implicit MediaController
:
<article> <style scoped> div { margin: 1em auto; position: relative; width: 400px; height: 300px; } video { position; absolute; bottom: 0; right: 0; } video:first-child { width: 100%; height: 100%; } video:last-child { width: 30%; } </style> <div> <video src="movie.vid#track=Video&track=English" autoplay controls mediagroup=movie></video> <video src="movie.vid#track=sign" autoplay mediagroup=movie></video> </div> </article>
A media element can have a group of associated text tracks, known as the media element's list of text tracks. The text tracks are sorted as follows:
track
element children of the media element, in tree order.addTextTrack()
method, in the order they were added, oldest first.A text track consists of:
This decides how the track is handled by the user agent. The kind is represented by a string. The possible strings are:
subtitles
captions
descriptions
chapters
metadata
The kind of track can change dynamically, in the case of a text track corresponding to a track
element.
This is a human-readable string intended to identify the track for the user. In certain cases, the label might be generated automatically.
The label of a track can change dynamically, in the case of a text track corresponding to a track
element or in the case of an automatically-generated label whose value depends on variable factors such as the user's preferred user interface language.
This is a string (a BCP 47 language tag) representing the language of the text track's cues. [BCP47]
The language of a text track can change dynamically, in the case of a text track corresponding to a track
element.
One of the following:
Indicates that the text track is known to exist (e.g. it has been declared with a track
element), but its cues have not been obtained.
Indicates that the text track is loading and there have been no fatal errors encountered so far. Further cues might still be added to the track.
Indicates that the text track has been loaded with no fatal errors. No new cues will be added to the track except if the text track corresponds to a MutableTextTrack
object.
Indicates that the text track was enabled, but when the user agent attempted to obtain it, this failed in some way (e.g. URL could not be resolved, network error, unknown text track format). Some or all of the cues are likely missing and will not be obtained.
The readiness state of a text track changes dynamically as the track is obtained.
One of the following:
Indicates that the text track is not active. Other than for the purposes of exposing the track in the DOM, the user agent is ignoring the text track. No cues are active, no events are fired, and the user agent will not attempt to obtain the track's cues.
Indicates that the text track is active, but that the user agent is not actively displaying the cues. If no attempt has yet been made to obtain the track's cues, the user agent will perform such an attempt momentarily. The user agent is maintaining a list of which cues are active, and events are being fired accordingly.
Indicates that the text track is active. If no attempt has yet been made to obtain the track's cues, the user agent will perform such an attempt momentarily. The user agent is maintaining a list of which cues are active, and events are being fired accordingly. In addition, for text tracks whose kind is subtitles
or captions
, the cues are being displayed over the video as appropriate; for text tracks whose kind is descriptions
, the user agent is making the cues available to the user in a non-visual fashion; and for text tracks whose kind is chapters
,
the user agent is making available to the user a mechanism by which the user can navigate to any point in the media resource by selecting a cue.
The showing by default state is used in conjunction with the default
attribute on track
elements to indicate that the text track was enabled due to that attribute. This allows the user agent to override the state if a later track is discovered that is more appropriate per the user's preferences.
A list of text track cues, along with rules for updating the text track rendering.
The list of cues of a text track can change dynamically, either because the text track has not yet been loaded or is still loading, or because the text track corresponds to a MutableTextTrack
object, whose API allows individual cues can be added or removed dynamically.
Each text track has a corresponding TextTrack
object.
The text tracks of a media element are ready if all the text tracks whose mode was not in the disabled state when the element's resource selection algorithm last started now have a text track readiness state of loaded or failed to load.
A text track cue is the unit of time-sensitive data in a text track, corresponding for instance for subtitles and captions to the text that appears at a particular time and disappears at another time.
Each text track cue consists of:
An arbitrary string.
A time, in seconds and fractions of a second, at which the cue becomes relevant.
A time, in seconds and fractions of a second, at which the cue stops being relevant.
A boolean indicating whether playback of the media resource is to pause when the cue stops being relevant.
A writing direction, either horizontal (a line extends horizontally and is positioned vertically, with consecutive lines displayed below each other), vertical growing left (a line extends vertically and is positioned horizontally, with consecutive lines displayed to the left of each other), or vertical growing right (a line extends vertically and is positioned horizontally, with consecutive lines displayed to the right of each other).
A number giving the size of the box within which the text of each line of the cue is to be aligned, to be interpreted as a percentage of the video, as defined by the writing direction.
The raw text of the cue, and rules for its interpretation, allowing the text to be rendered and converted to a DOM fragment.
A text track cue is immutable.
Each text track cue has a corresponding TextTrackCue
object, and can be associated with a particular text track. Once a text track cue is associated with a particular text track, the association is permanent.
In addition, each text track cue has two pieces of dynamic information:
This flag must be initially unset. The flag is used to ensure events are fired appropriately when the cue becomes active or inactive, and to make sure the right cues are rendered.
The user agent must synchronously unset this flag whenever the text track cue is removed from its text track's text track list of cues; whenever the text track itself is removed from its media element's list of text tracks or has its text track mode changed to disabled; and whenever the media element's readyState
is changed back to HAVE_NOTHING
. When the flag is unset in this way for one or more cues in text tracks that were showing or showing by default prior to the relevant incident, the user agent must, after having unset the flag for all the affected cues, apply the rules for updating the text track rendering of those text tracks.
This is used as part of the rendering model, to keep cues in a consistent position. It must initially be empty. Whenever the text track cue active flag is unset, the user agent must empty the text track cue display state.
The text track cues of a media element's text tracks are ordered relative to each other in the text track cue order, which is determined as follows: first group the cues by their text track, with the groups being sorted in the same order as their text tracks appear in the media element's list of text tracks; then, within each group, cues must be sorted by their start time, earliest first; then, any cues with the same start time must be sorted by their end time, earliest first; and finally, any cues with identical end times must be sorted in the order they were created (so e.g. for cues from a WebVTT file, that would be the order in which the cues were listed in the file).
A media-resource-specific text track is a text track that corresponds to data found in the media resource.
textTracks
. length
Returns the number of text tracks associated with the media element (e.g. from track
elements). This is the number of text tracks in the media element's list of text tracks.
textTracks[
n ]
Returns the TextTrack
object representing the nth text track in the media element's list of text tracks.
track
Returns the TextTrack
object representing the track
element's text track.
interface TextTrack { readonly attribute DOMString kind; readonly attribute DOMString label; readonly attribute DOMString language; const unsigned short NONE = 0; const unsigned short LOADING = 1; const unsigned short LOADED = 2; const unsigned short ERROR = 3; readonly attribute unsigned short readyState; attribute Function onload; attribute Function onerror; const unsigned short OFF = 0; const unsigned short HIDDEN = 1; const unsigned short SHOWING = 2; attribute unsigned short mode; readonly attribute TextTrackCueList cues; readonly attribute TextTrackCueList activeCues; attribute Function oncuechange; }; TextTrack implements EventTarget;
kind
Returns the text track kind string.
label
Returns the text track label.
language
Returns the text track language string.
readyState
Returns the text track readiness state, represented by a number from the following list:
TextTrack
. NONE
(0)The text track not loaded state.
TextTrack
. LOADING
(1)The text track loading state.
TextTrack
. LOADED
(2)The text track loaded state.
TextTrack
. ERROR
(3)The text track failed to load state.
mode
Returns the text track mode, represented by a number from the following list:
TextTrack
. OFF
(0)The text track disabled mode.
TextTrack
. HIDDEN
(1)The
mode.TextTrack
. SHOWING
(2)The text track showing and showing by default modes.
Can be set, to change the mode.
cues
Returns the text track list of cues, as a TextTrackCueList
object.
activeCues
Returns the text track cues from the text track list of cues that are currently active (i.e. that start before the current playback position and end after it), as a TextTrackCueList
object.
interface MutableTextTrack : TextTrack { void addCue(in TextTrackCue cue); void removeCue(in TextTrackCue cue); };
addTextTrack
( kind [, label [, language ] ] )Creates and returns a new MutableTextTrack
object, which is also added to the media element's list of text tracks.
addCue
( cue )Adds the given cue to mutableTextTrack's text track list of cues.
Raises an exception if the argument is null, associated with another text track, or already in the list of cues.
removeCue
( cue )Removes the given cue from mutableTextTrack's text track list of cues.
Raises an exception if the argument is null, associated with another text track, or not in the list of cues.
In this example, an audio
element is used to play a specific sound-effect from a sound file containing many sound effects. A cue is used to pause the audio, so that it ends exactly at the end of the clip, even if the browser is busy running some script. If the page had relied on script to pause the audio, then the start of the next clip might be heard if the browser was not able to run the script at the exact time specified.
var sfx = new Audio('sfx.wav'); var sounds = a.addTextTrack('metadata'); // add sounds we care about sounds.addCue(new TextTrackCue('dog bark', 12.783, 13.612, '', '', '', true)); sounds.addCue(new TextTrackCue('kitten mew', 13.612, 15.091, '', '', '', true)); function playSound(id) { sfx.currentTime = sounds.getCueById(id).startTime; sfx.play(); } sfx.oncanplaythrough = function () { playSound('dog bark'); } window.onbeforeunload = function () { playSound('kitten mew'); return 'Are you sure you want to leave this awesome page?'; }
interface TextTrackCueList { readonly attribute unsigned long length; getter TextTrackCue (in unsigned long index); TextTrackCue getCueById(in DOMString id); };
length
Returns the number of cues in the list.
Returns the text track cue with index index in the list. The cues are sorted in text track cue order.
getCueById
( id )Returns the first text track cue (in text track cue order) with text track cue identifier id.
Returns null if none of the cues have the given identifier or if the argument is the empty string.
interface TextTrackCue { readonly attribute TextTrack track; readonly attribute DOMString id; readonly attribute double startTime; readonly attribute double endTime; readonly attribute boolean pauseOnExit; DOMString getCueAsSource(); DocumentFragment getCueAsHTML(); attribute Function ; attribute Function ; }; TextTrackCue implements EventTarget;
Returns the TextTrack
object to which this text track cue belongs, if any, or null otherwise.
Returns the text track cue identifier.
Returns the text track cue start time, in seconds.
Returns the text track cue end time, in seconds.
Returns true if the text track cue pause-on-exit flag is set, false otherwise.
Returns the text track cue text in raw unparsed form.
Returns the text track cue text as a DocumentFragment
of HTML elements and other DOM nodes.
The controls
attribute is a boolean attribute. If present, it indicates that the author has not provided a scripted controller and would like the user agent to provide its own set of controls.
The controls
IDL attribute must reflect the content attribute of the same name.
volume
[ = value ]Returns the current playback volume, as a number in the range 0.0 to 1.0, where 0.0 is the quietest and 1.0 the loudest.
Can be set, to change the volume.
Throws an INDEX_SIZE_ERR
if the new value is not in the range 0.0 .. 1.0.
muted
[ = value ]Returns true if audio is muted, overriding the volume
attribute, and false if the volume
attribute is being honored.
Can be set, to change whether the audio is muted or not.
The muted
attribute on the video
element controls the default state of the audio channel of the media resource, potentially overriding user preferences.
The defaultMuted
IDL attribute must reflect the muted
content attribute.
This attribute has no dynamic effect (it only controls the default state of the element).
This video (an advertisment) autoplays, but to avoid annoying users, it does so without sound, and allows the user to turn the sound on.
<video src="adverts.cgi?kind=video" controls autoplay loop muted></video>
Objects implementing the TimeRanges
interface represent a list of ranges (periods) of time.
interface TimeRanges { readonly attribute unsigned long length; double start(in unsigned long index); double end(in unsigned long index); };
length
Returns the number of ranges in the object.
start
(index)Returns the time for the start of the range with the given index.
Throws an INDEX_SIZE_ERR
if the index is out of range.
end
(index)Returns the time for the end of the range with the given index.
Throws an INDEX_SIZE_ERR
if the index is out of range.
The following events fire on media elements as part of the processing model described above:
Event name | Interface | Dispatched when... | Preconditions |
---|---|---|---|
loadstart |
Event |
The user agent begins looking for media data, as part of the resource selection algorithm. | networkState equals NETWORK_LOADING |
progress |
Event |
The user agent is fetching media data. | networkState equals NETWORK_LOADING |
suspend |
Event |
The user agent is intentionally not currently fetching media data, but does not have the entire media resource downloaded. | networkState equals NETWORK_IDLE |
abort |
Event |
The user agent stops fetching the media data before it is completely downloaded, but not due to an error. | error is an object with the code MEDIA_ERR_ABORTED . networkState equals either NETWORK_EMPTY or NETWORK_IDLE , depending on when the download was aborted. |
error |
Event |
An error occurs while fetching the media data. | error is an object with the code MEDIA_ERR_NETWORK or higher. networkState equals either NETWORK_EMPTY or NETWORK_IDLE , depending on when the download was aborted. |
emptied |
Event |
A media element whose networkState was previously not in the NETWORK_EMPTY state has just switched to that state (either because of a fatal error during load that's about to be reported, or because the load() method was invoked while the resource selection algorithm was already running). |
networkState is NETWORK_EMPTY ; all the IDL attributes are in their initial states. |
stalled |
Event |
The user agent is trying to fetch media data, but data is unexpectedly not forthcoming. | networkState is NETWORK_LOADING . |
loadedmetadata |
Event |
The user agent has just determined the duration and dimensions of the media resource and the text tracks are ready. | readyState is newly equal to HAVE_METADATA or greater for the first time. |
loadeddata |
Event |
The user agent can render the media data at the current playback position for the first time. | readyState newly increased to HAVE_CURRENT_DATA or greater for the first time. |
canplay |
Event |
The user agent can resume playback of the media data, but estimates that if playback were to be started now, the media resource could not be rendered at the current playback rate up to its end without having to stop for further buffering of content. | readyState newly increased to HAVE_FUTURE_DATA or greater. |
canplaythrough |
Event |
The user agent estimates that if playback were to be started now, the media resource could be rendered at the current playback rate all the way to its end without having to stop for further buffering. | readyState is newly equal to HAVE_ENOUGH_DATA . |
playing |
Event |
Playback is ready to start after having been paused or delayed due to lack of media data. | readyState is newly equal to or greater than HAVE_FUTURE_DATA and paused is false, or paused is newly false and readyState is equal to or greater than HAVE_FUTURE_DATA . Even if this event fires, the element might still not be potentially playing, e.g. if the element
is blocked on its media controller (e.g. because the current media controller is paused, or another slaved media element is stalled somehow, or because the media resource has no data corresponding to the media controller position), or the element is paused for user interaction. |
waiting |
Event |
Playback has stopped because the next frame is not available, but the user agent expects that frame to become available in due course. | readyState is equal to or less than HAVE_CURRENT_DATA , and paused is false. Either seeking is true, or the current playback position is not contained in any of the ranges in buffered . It is possible for playback to stop for other reasons without paused being false, but those reasons do not fire
this event (and when those situations resolve, a separate playing event is not fired either): e.g. the element is newly blocked on its media controller, or playback ended, or playback stopped due to errors, or the element has paused for user interaction. |
seeking |
Event |
The seeking IDL attribute changed to true and the seek operation is taking long enough that the user agent has time to fire the event. |
|
seeked |
Event |
The seeking IDL attribute changed to false. |
|
ended |
Event |
Playback has stopped because the end of the media resource was reached. | currentTime equals the end of the media resource; ended is true. |
durationchange |
Event |
The duration attribute has just been updated. |
|
timeupdate |
Event |
The current playback position changed as part of normal playback or in an especially interesting way, for example discontinuously. | |
play |
Event |
The element is no longer paused. Fired after the play() method has returned, or when the autoplay attribute has caused playback to begin. |
paused is newly false. |
pause |
Event |
The element has been paused. Fired after the pause() method has returned. |
paused is newly true. |
ratechange |
Event |
Either the defaultPlaybackRate or the playbackRate attribute has just been updated. |
|
volumechange |
Event |
Either the volume attribute or the muted attribute has changed. Fired after the relevant attribute's setter has returned. |
The following events fire on MediaController
objects:
Event name | Interface | Dispatched when... |
---|---|---|
emptied |
Event |
All the slaved media elements newly have readyState set to HAVE_NOTHING or greater, or there are no longer any slaved media elements. |
loadedmetadata |
Event |
All the slaved media elements newly have readyState set to HAVE_METADATA or greater. |
loadeddata |
Event |
All the slaved media elements newly have readyState set to HAVE_CURRENT_DATA or greater. |
canplay |
Event |
All the slaved media elements newly have readyState set to HAVE_FUTURE_DATA or greater. |
canplaythrough |
Event |
All the slaved media elements newly have readyState set to HAVE_ENOUGH_DATA or greater. |
playing |
Event |
The MediaController is no longer a blocked media controller. |
waiting |
Event |
The MediaController is now a blocked media controller. |
ended |
Event |
All the slaved media elements have newly ended playback. |
durationchange |
Event |
The duration attribute has just been updated. |
timeupdate |
Event |
The media controller position changed. |
play |
Event |
The paused attribute is newly false. |
pause |
Event |
The paused attribute is newly true. |
ratechange |
Event |
Either the defaultPlaybackRate attribute or the playbackRate attribute has just been updated. |
volumechange |
Event |
Either the volume attribute or the muted attribute has just been updated. |
Playing audio and video resources on small devices such as set-top boxes or mobile phones is often constrained by limited hardware resources in the device. For example, a device might only support three simultaneous videos. For this reason, it is a good practice to release resources held by media elements when they are done playing, either by being very careful about removing all references to the element and allowing it to be garbage collected, or, even better, by removing the element's src
attribute and any source
element descendants, and invoking the element's load()
method.
Similarly, when the playback rate is not exactly 1.0, hardware, software, or format limitations can cause video frames to be dropped and audio to be choppy or muted.
canvas
elementwidth
height
interface HTMLCanvasElement : HTMLElement {
attribute unsigned long width;
attribute unsigned long height;
DOMString toDataURL(in optional DOMString type, in any... args);
void toBlob(in FileCallback, in optional DOMString type, in any... args);
object getContext(in DOMString contextId, in any... args);
};
The canvas
element provides scripts with a resolution-dependent bitmap canvas, which can be used for rendering graphs, game graphics, or other visual images on the fly.
Authors should not use the canvas
element in a document when a more suitable element is available. For example, it is inappropriate to use a canvas
element to render a page heading: if the desired presentation of the heading is graphically intense, it should be marked up using appropriate elements (typically h1
) and then styled using CSS and supporting technologies such as XBL.
When authors use the canvas
element, they must also provide content that, when presented to the user, conveys essentially the same function or purpose as the bitmap canvas. This content may be placed as content of the canvas
element. The contents of the canvas
element, if any, are the element's fallback content.
In interactive visual media, if scripting is enabled for the canvas
element, and if support for canvas
elements has been enabled, the canvas
element represents embedded content consisting of a dynamically created image.
In non-interactive, static, visual media, if the canvas
element has been previously painted on (e.g. if the page was viewed in an interactive visual medium and is now being printed, or if some script that ran during the page layout process painted on the element), then the canvas
element represents embedded content with the current image and size. Otherwise, the element represents its fallback content instead.
In non-visual media, and in visual media if scripting is disabled for the canvas
element or if support for canvas
elements has been disabled, the canvas
element represents its fallback content instead.
When a canvas
element represents embedded content, the user can still focus descendants of the canvas
element (in the fallback content). When an element is focused, it is the target of keyboard interaction events (even though the element itself is not visible). This allows authors to make an interactive canvas keyboard-accessible: authors should have a one-to-one mapping of interactive regions to focusable elements in the fallback content. (Focus has no effect on mouse interaction events.) [DOMEVENTS]
The canvas
element has two attributes to control the size of the coordinate space: width
and height
. These attributes, when specified, must have values that are valid non-negative integers. The width
attribute defaults to 300, and the height
attribute defaults to 150.
The intrinsic dimensions of the canvas
element equal the size of the coordinate space, with the numbers interpreted in CSS pixels. However, the element can be sized arbitrarily by a style sheet. During rendering, the image is scaled to fit this layout size.
The width
and height
IDL attributes must reflect the respective content attributes of the same name, with the same defaults.
Only one square appears to be drawn in the following example:
// canvas is a reference to a <canvas> element var context = canvas.getContext('2d'); context.fillRect(0,0,50,50); canvas.setAttribute('width', '300'); // clears the canvas context.fillRect(0,100,50,50); canvas.width = canvas.width; // clears the canvas context.fillRect(100,0,50,50); // only this square remains
getContext
(contextId [, ... ])Returns an object that exposes an API for drawing on the canvas. The first argument specifies the desired API. Subsequent arguments are handled by that API.
The list of defined contexts is given on the WHATWG Wiki CanvasContexts page. [WHATWGWIKI]
Returns null if the given context ID is not supported or if the canvas has already been initialised with some other (incompatible) context type (e.g. trying to get a "2d
" context after getting a "webgl
" context).
toDataURL
( [ type, ... ])Returns a data:
URL for the image in the canvas.
The first argument, if provided, controls the type of the image to be returned (e.g. PNG or JPEG). The default is image/png
; that type is also used if the given type isn't supported. The other arguments are specific to the type, and control the way that the image is generated, as given in the table below.
When trying to use types other than "image/png
", authors can check if the image was really returned in the requested format by checking to see if the returned string starts with one of the exact strings "data:image/png,
" or "data:image/png;
". If it does, the image is PNG, and thus the requested type was not supported. (The one exception to this is if the canvas has either no height or no width, in which case the result might simply be "data:,
".)
toBlob
(callback [, type, ... ])Creates a Blob
object representing a file containing the image in the canvas, and invokes a callback with a handle to that object.
The second argument, if provided, controls the type of the image to be returned (e.g. PNG or JPEG). The default is image/png
; that type is also used if the given type isn't supported. The other arguments are specific to the type, and control the way that the image is generated, as given in the table below.
Type | Other arguments | Reference |
---|---|---|
image/jpeg |
The second argument is a number in the range 0.0 to 1.0 inclusive treated as the desired quality level. | [JPEG] |
map
elementname
interface HTMLMapElement : HTMLElement { attribute DOMString name; readonly attribute HTMLCollection areas; readonly attribute HTMLCollection images; };
The map
element, in conjunction with any area
element descendants, defines an image map. The element represents its children.
The name
attribute gives the map a name so that it can be referenced. The attribute must be present and must have a non-empty value with no space characters. The value of the name
attribute must not be a compatibility-caseless match for the value of the name
attribute of another map
element in the same document. If the id
attribute is also specified, both attributes must have the same value.
areas
Returns an HTMLCollection
of the area
elements in the map
.
images
Returns an HTMLCollection
of the img
and object
elements that use the map
.
The IDL attribute name
must reflect the content attribute of the same name.
Image maps can be defined in conjunction with other content on the page, to ease maintenance. This example is of a page with an image map at the top of the page and a corresponding set of text links at the bottom.
<!DOCTYPE HTML> <TITLE>Babies™: Toys</TITLE> <HEADER> <H1>Toys</H1> <IMG SRC="/images/menu.gif" ALT="Babies™ navigation menu. Select a department to go to its page." USEMAP="#NAV"> </HEADER> ... <FOOTER> <MAP NAME="NAV"> <P> <A HREF="/clothes/">Clothes</A> <AREA ALT="Clothes" COORDS="0,0,100,50" HREF="/clothes/"> | <A HREF="/toys/">Toys</A> <AREA ALT="Toys" COORDS="0,0,100,50" HREF="/toys/"> | <A HREF="/food/">Food</A> <AREA ALT="Food" COORDS="0,0,100,50" HREF="/food/"> | <A HREF="/books/">Books</A> <AREA ALT="Books" COORDS="0,0,100,50" HREF="/books/"> </MAP> </FOOTER>
area
elementmap
element ancestor.alt
coords
shape
href
target
rel
media
hreflang
type
interface HTMLAreaElement : HTMLElement { attribute DOMString alt; attribute DOMString coords; attribute DOMString shape; stringifier attribute DOMString href; attribute DOMString target; attribute DOMString rel; readonly attribute DOMTokenList relList; attribute DOMString media; attribute DOMString hreflang; attribute DOMString type; // URL decomposition IDL attributes attribute DOMString protocol; attribute DOMString host; attribute DOMString hostname; attribute DOMString port; attribute DOMString pathname; attribute DOMString search; attribute DOMString hash; };
The area
element represents either a hyperlink with some text and a corresponding area on an image map, or a dead area on an image map.
If the area
element has an href
attribute, then the area
element represents a hyperlink. In this case, the alt
attribute must be present. It specifies the text of the hyperlink. Its value must be text that, when presented with the texts specified for the other hyperlinks of the image map, and with the alternative text of the image, but without the image itself, provides the user with the same kind of choice as the hyperlink would when used without its text but with its shape applied to the image. The alt
attribute may be left blank
if there is another area
element in the same image map that points to the same resource and has a non-blank alt
attribute.
If the area
element has no href
attribute, then the area represented by the element cannot be selected, and the alt
attribute must be omitted.
In both cases, the shape
and coords
attributes specify the area.
The shape
attribute is an enumerated attribute. The following table lists the keywords defined for this attribute. The states given in the first cell of the rows with keywords give the states to which those keywords map.
State | Keywords | |
---|---|---|
Circle state | circle |
|
Default state | default |
|
Polygon state | poly |
|
Rectangle state | rect |
|
The attribute may be omitted. The missing value default is the rectangle state.
The coords
attribute must, if specified, contain a valid list of integers. This attribute gives the coordinates for the shape described by the shape
attribute.
In the circle state, area
elements must have a coords
attribute present, with three integers, the last of which must be non-negative. The first integer must be the distance in CSS pixels from the left edge of the image to the center of the circle, the second integer must be the distance in CSS pixels from the top edge of the image to the center of the circle, and the third integer must be the radius of the circle, again in CSS pixels.
In the default state state, area
elements must not have a coords
attribute. (The area is the whole image.)
In the polygon state, area
elements must have a coords
attribute with at least six integers, and the number of integers must be even. Each pair of integers must represent a coordinate given as the distances from the left and the top of the image in CSS pixels respectively, and all the coordinates together must represent the points of the polygon, in order.
In the rectangle state, area
elements must have a coords
attribute with exactly four integers, the first of which must be less than the third, and the second of which must be less than the fourth. The four points must represent, respectively, the distance from the left edge of the image to the left side of the rectangle, the distance from the top edge to the top side, the distance from the left edge to the right side, and the distance from the top edge to the bottom side, all in CSS pixels.
The target
, rel
, media
, hreflang
, and type
attributes must be omitted if the href
attribute is not present.
The IDL attributes alt
, coords
, href
, target
, rel
, media
, hreflang
, and type
, each must reflect the respective content attributes of the same name.
The IDL attribute shape
must reflect the shape
content attribute.
The IDL attribute relList
must reflect the rel
content attribute.
The area
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the
element's href
attribute to the new output value.
An image map allows geometric areas on an image to be associated with hyperlinks.
An image, in the form of an img
element or an object
element representing an image, may be associated with an image map (in the form of a map
element) by specifying a usemap
attribute on the img
or object
element. The usemap
attribute, if specified, must be a valid hash-name reference to a map
element.
Consider an image that looks as follows:
If we wanted just the colored areas to be clickable, we could do it as follows:
<p> Please select a shape: <img src="shapes.png" usemap="#shapes" alt="Four shapes are available: a red hollow box, a green circle, a blue triangle, and a yellow four-pointed star."> <map name="shapes"> <area shape=rect coords="50,50,100,100"> <!-- the hole in the red box --> <area shape=rect coords="25,25,125,125" href="red.html" alt="Red box."> <area shape=circle coords="200,75,50" href="green.html" alt="Green circle."> <area shape=poly coords="325,25,262,125,388,125" href="blue.html" alt="Blue triangle."> <area shape=poly coords="450,25,435,60,400,75,435,90,450,125,465,90,500,75,465,60" href="yellow.html" alt="Yellow star."> </map> </p>
The math
element from the MathML namespace falls into the embedded content, phrasing content, and flow content categories for the purposes of the content models in this specification.
The semantics of MathML elements are defined by the MathML specification and other applicable specifications. [MATHML]
Here is an example of the use of MathML in an HTML document:
<!DOCTYPE html> <html> <head> <title>The quadratic formula</title> </head> <body> <h1>The quadratic formula</h1> <p> <math> <mi>x</mi> <mo>=</mo> <mfrac> <mrow> <mo form="prefix">−</mo> <mi>b</mi> <mo>±</mo> <msqrt> <msup> <mi>b</mi> <mn>2</mn> </msup> <mo>−</mo> <mn>4</mn> <mo></mo> <mi>a</mi> <mo></mo> <mi>c</mi> </msqrt> </mrow> <mrow> <mn>2</mn> <mo></mo> <mi>a</mi> </mrow> </mfrac> </math> </p> </body> </html>
The svg
element from the SVG namespace falls into the embedded content, phrasing content, and flow content categories for the purposes of the content models in this specification.
When the SVG foreignObject
element contains elements from the HTML namespace, such elements must all be flow content. [SVG]
The content model for title
elements in the SVG namespace inside HTML documents is phrasing content. (This further constrains the requirements given in the SVG specification.)
The semantics of SVG elements are defined by the SVG specification and other applicable specifications. [SVG]
The SVG specification includes requirements regarding the handling of elements in the DOM that are not in the SVG namespace, that are in SVG fragments, and that are not included in a foreignObject
element. This specification does not define any processing for elements in SVG fragments that are not in the HTML namespace; they are considered neither conforming nor non-conforming from the perspective of this specification.
The width
and height
attributes on img
, iframe
, embed
, object
, video
, and, when their type
attribute is in the Image Button state, input
elements may be specified to give the dimensions of the visual content of the element (the width and height respectively, relative to the
nominal direction of the output medium), in CSS pixels. The attributes, if specified, must have values that are valid non-negative integers.
The specified dimensions given may differ from the dimensions specified in the resource itself, since the resource may have a resolution that differs from the CSS pixel resolution. (On screens, CSS pixels have a resolution of 96ppi, but in general the CSS pixel resolution depends on the reading distance.) If both attributes are specified, then one of the following statements must be true:
The target ratio is the ratio of the intrinsic width to the intrinsic height in the resource. The specified width and specified height are the values of the width
and height
attributes respectively.
The two attributes must be omitted if the resource in question does not have both an intrinsic width and an intrinsic height.
If the two attributes are both zero, it indicates that the element is not intended for the user (e.g. it might be a part of a service to count page views).
The dimension attributes are not intended to be used to stretch the image.
The width
and height
IDL attributes on the iframe
, embed
, object
, and video
elements must reflect the respective content attributes of the same name.
The table element.
table
elementcaption
element, followed by zero or more colgroup
elements, followed optionally by a thead
element, followed optionally by a tfoot
element, followed by either zero or more tbody
elements or one or more tr
elements, followed optionally by a tfoot
element (but there can only be one tfoot
element child in total).border
interface HTMLTableElement : HTMLElement { attribute HTMLTableCaptionElement caption; HTMLElement createCaption(); void deleteCaption(); attribute HTMLTableSectionElement tHead; HTMLElement createTHead(); void deleteTHead(); attribute HTMLTableSectionElement tFoot; HTMLElement createTFoot(); void deleteTFoot(); readonly attribute HTMLCollection tBodies; HTMLElement createTBody(); readonly attribute HTMLCollection rows; HTMLElement insertRow(in optional long index); void deleteRow(in long index); attribute DOMString border; };
The table
element represents data with more than one dimension, in the form of a table.
Tables have rows, columns, and cells given by their descendants. The rows and columns form a grid; a table's cells must completely cover that grid without overlap.
Authors are encouraged to provide information describing how to interpret complex tables. Guidance on how provide such information is given below.
Tables should not be used as layout aids. Historically, many Web authors have tables in HTML as a way to control their page layout making it difficult to extract tabular data from such documents. In particular, users of accessibility tools, like screen readers, are likely to find it very difficult to navigate pages with tables used for layout. If a table is to be used for layout it must be marked with the attribute role="presentation" for a user agent to properly represent the table to an assistive technology and to properly convey the intent of the author to tools that wish to extract tabular data from the document.
There are a variety of alternatives to using HTML tables for layout, primarily using CSS positioning and the CSS table model.
The border
attribute may be specified on a table
element to explicitly indicate that the table
element is not being used for layout purposes. If specified, the attribute's value must either be the empty string or the value "1
". The attribute is used by certain user agents as an indication that borders should be drawn around cells of the table.
Authors are encouraged to consider using some of the table layout techniques described below to make tables easier to navigate for users.
caption
[ = value ]Returns the table's caption
element.
Can be set, to replace the caption
element. If the new value is not a caption
element, throws a HIERARCHY_REQUEST_ERR
exception.
createCaption
()Ensures the table has a caption
element, and returns it.
deleteCaption
()Ensures the table does not have a caption
element.
tHead
[ = value ]Returns the table's thead
element.
Can be set, to replace the thead
element. If the new value is not a thead
element, throws a HIERARCHY_REQUEST_ERR
exception.
createTHead
()Ensures the table has a thead
element, and returns it.
deleteTHead
()Ensures the table does not have a thead
element.
tFoot
[ = value ]Returns the table's tfoot
element.
Can be set, to replace the tfoot
element. If the new value is not a tfoot
element, throws a HIERARCHY_REQUEST_ERR
exception.
createTFoot
()Ensures the table has a tfoot
element, and returns it.
deleteTFoot
()Ensures the table does not have a tfoot
element.
tBodies
Returns an HTMLCollection
of the tbody
elements of the table.
createTBody
()Creates a tbody
element, inserts it into the table, and returns it.
rows
Returns an HTMLCollection
of the tr
elements of the table.
insertRow
(index)Creates a tr
element, along with a tbody
if required, inserts them into the table at the position given by the argument, and returns the tr
.
The position is relative to the rows in the table. The index −1 is equivalent to inserting at the end of the table.
If the given position is less than −1 or greater than the number of rows, throws an INDEX_SIZE_ERR
exception.
deleteRow
(index)Removes the tr
element with the given position in the table.
The position is relative to the rows in the table. The index −1 is equivalent to deleting the last row of the table.
If the given position is less than −1 or greater than the index of the last row, or if there are no rows, throws an INDEX_SIZE_ERR
exception.
The border
IDL attribute must reflect the content attribute of the same name.
Here is an example of a table being used to mark up a Sudoku puzzle. Observe the lack of headers, which are not necessary in such a table.
<section> <style scoped> table { border-collapse: collapse; border: solid thick; } colgroup, tbody { border: solid medium; } td { border: solid thin; height: 1.4em; width: 1.4em; text-align: center; padding: 0; } </style> <h1>Today's Sudoku</h1> <table> <colgroup><col><col><col> <colgroup><col><col><col> <colgroup><col><col><col> <tbody> <tr> <td> 1 <td> <td> 3 <td> 6 <td> <td> 4 <td> 7 <td> <td> 9 <tr> <td> <td> 2 <td> <td> <td> 9 <td> <td> <td> 1 <td> <tr> <td> 7 <td> <td> <td> <td> <td> <td> <td> <td> 6 <tbody> <tr> <td> 2 <td> <td> 4 <td> <td> 3 <td> <td> 9 <td> <td> 8 <tr> <td> <td> <td> <td> <td> <td> <td> <td> <td> <tr> <td> 5 <td> <td> <td> 9 <td> <td> 7 <td> <td> <td> 1 <tbody> <tr> <td> 6 <td> <td> <td> <td> 5 <td> <td> <td> <td> 2 <tr> <td> <td> <td> <td> <td> 7 <td> <td> <td> <td> <tr> <td> 9 <td> <td> <td> 8 <td> <td> 2 <td> <td> <td> 5 </table> </section>
For tables that consist of more than just a grid of cells with headers in the first row and headers in the first column, and for any table in general where the reader might have difficulty understanding the content, authors should include explanatory information introducing the table. This information is useful for all users, but is especially useful for users who cannot see the table, e.g. users of screen readers.
Such explanatory information should introduce the purpose of the table, outline its basic cell structure, highlight any trends or patterns, and generally teach the user how to use the table.
For instance, the following table:
Negative | Characteristic | Positive |
---|---|---|
Sad | Mood | Happy |
Failing | Grade | Passing |
...might benefit from a description explaining the way the table is laid out, something like "Characteristics are given in the second column, with the negative side in the left column and the positive side in the right column".
There are a variety of ways to include this information, such as:
<p>In the following table, characteristics are given in the second column, with the negative side in the left column and the positive side in the right column.</p> <table> <caption>Characteristics with positive and negative sides</caption> <thead> <tr> <th id="n"> Negative <th> Characteristic <th> Positive <tbody> <tr> <td headers="n r1"> Sad <th id="r1"> Mood <td> Happy <tr> <td headers="n r2"> Failing <th id="r2"> Grade <td> Passing </table>
caption
<table> <caption> <strong>Characteristics with positive and negative sides.</strong> <p>Characteristics are given in the second column, with the negative side in the left column and the positive side in the right column.</p> </caption> <thead> <tr> <th id="n"> Negative <th> Characteristic <th> Positive <tbody> <tr> <td headers="n r1"> Sad <th id="r1"> Mood <td> Happy <tr> <td headers="n r2"> Failing <th id="r2"> Grade <td> Passing </table>
caption
, in a details
element<table> <caption> <strong>Characteristics with positive and negative sides.</strong> <details> <summary>Help</summary> <p>Characteristics are given in the second column, with the negative side in the left column and the positive side in the right column.</p> </details> </caption> <thead> <tr> <th id="n"> Negative <th> Characteristic <th> Positive <tbody> <tr> <td headers="n r1"> Sad <th id="r1"> Mood <td> Happy <tr> <td headers="n r2"> Failing <th id="r2"> Grade <td> Passing </table>
figure
<figure> <figcaption>Characteristics with positive and negative sides</figcaption> <p>Characteristics are given in the second column, with the negative side in the left column and the positive side in the right column.</p> <table> <thead> <tr> <th id="n"> Negative <th> Characteristic <th> Positive <tbody> <tr> <td headers="n r1"> Sad <th id="r1"> Mood <td> Happy <tr> <td headers="n r2"> Failing <th id="r2"> Grade <td> Passing </table> </figure>
figure
's figcaption
<figure> <figcaption> <strong>Characteristics with positive and negative sides</strong> <p>Characteristics are given in the second column, with the negative side in the left column and the positive side in the right column.</p> </figcaption> <table> <thead> <tr> <th id="n"> Negative <th> Characteristic <th> Positive <tbody> <tr> <td headers="n r1"> Sad <th id="r1"> Mood <td> Happy <tr> <td headers="n r2"> Failing <th id="r2"> Grade <td> Passing </table> </figure>
Authors may also use other techniques, or combinations of the above techniques, as appropriate.
The best option, of course, rather than writing a description explaining the way the table is laid out, is to adjust the table such that no explanation is needed.
In the case of the table used in the examples above, a simple rearrangement of the table so that the headers are on the top and left sides removes the need for an explanation as well as removing the need for the use of headers
attributes:
<table> <caption>Characteristics with positive and negative sides</caption> <thead> <tr> <th> Characteristic <th> Negative <th> Positive <tbody> <tr> <th> Mood <td> Sad <td> Happy <tr> <th> Grade <td> Failing <td> Passing </table>
Good table layout is key to making tables more readable and usable.
In visual media, providing column and row borders and alternating row backgrounds can be very effective to make complicated tables more readable.
For tables with large volumes of numeric content, using monospaced fonts can help users see patterns, especially in situations where a user agent does not render the borders. (Unfortunately, for historical reasons, not rendering borders on tables is a common default.)
In speech media, table cells can be distinguished by reporting the corresponding headers before reading the cell's contents, and by allowing users to navigate the table in a grid fashion, rather than serializing the entire contents of the table in source order.
Authors are encouraged to use CSS to achieve these effects.
caption
elementtable
element.table
elements.interface HTMLTableCaptionElement : HTMLElement {};
The caption
element represents the title of the table
that is its parent, if it has a parent and that is a table
element.
When a table
element is the only content in a figure
element other than the figcaption
, the caption
element should be omitted in favor of the figcaption
.
A caption can introduce context for a table, making it significantly easier to understand.
Consider, for instance, the following table:
1 | 2 | 3 | 4 | 5 | 6 | |
---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 |
2 | 3 | 4 | 5 | 6 | 7 | 8 |
3 | 4 | 5 | 6 | 7 | 8 | 9 |
4 | 5 | 6 | 7 | 8 | 9 | 10 |
5 | 6 | 7 | 8 | 9 | 10 | 11 |
6 | 7 | 8 | 9 | 10 | 11 | 12 |
In the abstract, this table is not clear. However, with a caption giving the table's number (for reference in the main prose) and explaining its use, it makes more sense:
<caption> <p>Table 1. <p>This table shows the total score obtained from rolling two six-sided dice. The first row represents the value of the first die, the first column the value of the second die. The total is given in the cell that corresponds to the values of the two dice. </caption>
colgroup
elementtable
element, after any caption
elements and before any thead
, tbody
, tfoot
, and tr
elements.span
attribute is present: Empty.span
attribute is absent: Zero or more col
elements.span
interface HTMLTableColElement : HTMLElement { attribute unsigned long span; };
The colgroup
element represents a group of one or more columns in the table
that is its parent, if it has a parent and that is a table
element.
If the colgroup
element contains no col
elements, then the element may have a span
content attribute specified, whose value must be a valid non-negative integer greater than zero.
The span
IDL attribute must reflect the content attribute of the same name. The value must be limited to only non-negative numbers greater than zero.
col
elementcolgroup
element that doesn't have a span
attribute.span
HTMLTableColElement
, same as for colgroup
elements. This interface defines one member, span
.
If a col
element has a parent and that is a colgroup
element that itself has a parent that is a table
element, then the col
element represents one or more columns in the column group represented by that
colgroup
.
The element may have a span
content attribute specified, whose value must be a valid non-negative integer greater than zero.
The span
IDL attribute must reflect the content attribute of the same name. The value must be limited to only non-negative numbers greater than zero.
tbody
elementtable
element, after any caption
, colgroup
, and thead
elements, but only if there are no tr
elements that are children of the table
element.tr
elementsinterface HTMLTableSectionElement : HTMLElement { readonly attribute HTMLCollection rows; HTMLElement insertRow(in optional long index); void deleteRow(in long index); };
The HTMLTableSectionElement
interface is also used for thead
and tfoot
elements.
The tbody
element represents a block of rows that consist of a body of data for the parent table
element, if the tbody
element has a parent and it is a table
.
rows
Returns an HTMLCollection
of the tr
elements of the table section.
insertRow
( [ index ] )Creates a tr
element, inserts it into the table section at the position given by the argument, and returns the tr
.
The position is relative to the rows in the table section. The index −1, which is the default if the argument is omitted, is equivalent to inserting at the end of the table section.
If the given position is less than −1 or greater than the number of rows, throws an INDEX_SIZE_ERR
exception.
deleteRow
(index)Removes the tr
element with the given position in the table section.
The position is relative to the rows in the table section. The index −1 is equivalent to deleting the last row of the table section.
If the given position is less than −1 or greater than the index of the last row, or if there are no rows, throws an INDEX_SIZE_ERR
exception.
thead
elementtable
element, after any caption
, and colgroup
elements and before any tbody
, tfoot
, and tr
elements, but only if there are no other thead
elements that are children of the table
element.tr
elementsHTMLTableSectionElement
, as defined for tbody
elements.The thead
element represents the block of rows that consist of the column labels (headers) for the parent table
element, if the thead
element has a parent and it is a table
.
This example shows a thead
element being used. Notice the use of both th
and td
elements in the thead
element: the first row is the headers, and the second row is an explanation of how to fill in the table.
<table> <caption> School auction sign-up sheet </caption> <thead> <tr> <th><label for=e1>Name</label> <th><label for=e2>Product</label> <th><label for=e3>Picture</label> <th><label for=e4>Price</label> <tr> <td>Your name here <td>What are you selling? <td>Link to a picture <td>Your reserve price <tbody> <tr> <td>Ms Danus <td>Doughnuts <td><img src="http://example.com/mydoughnuts.png" title="Doughnuts from Ms Danus"> <td>$45 <tr> <td><input id=e1 type=text name=who required form=f> <td><input id=e2 type=text name=what required form=f> <td><input id=e3 type=url name=pic form=f> <td><input id=e4 type=number step=0.01 min=0 value=0 required form=f> </table> <form id=f action="/auction.cgi"> <input type=button name=add value="Submit"> </form>
tfoot
elementtable
element, after any caption
, colgroup
, and thead
elements and before any tbody
and tr
elements, but only if there are no other tfoot
elements that are children of the table
element.table
element, after any caption
, colgroup
, thead
, tbody
, and tr
elements, but only if there are no other tfoot
elements that are children of the table
element.tr
elementsHTMLTableSectionElement
, as defined for tbody
elements.The tfoot
element represents the block of rows that consist of the column summaries (footers) for the parent table
element, if the tfoot
element has a parent and it is a table
.
tr
elementthead
element.tbody
element.tfoot
element.table
element, after any caption
, colgroup
, and thead
elements, but only if there are no tbody
elements that are children of the table
element.td
or th
elementsinterface HTMLTableRowElement : HTMLElement { readonly attribute long rowIndex; readonly attribute long sectionRowIndex; readonly attribute HTMLCollection cells; HTMLElement insertCell(in optional long index); void deleteCell(in long index); };
The tr
element represents a row of cells in a table.
rowIndex
Returns the position of the row in the table's rows
list.
Returns −1 if the element isn't in a table.
sectionRowIndex
Returns the position of the row in the table section's rows
list.
Returns −1 if the element isn't in a table section.
cells
Returns an HTMLCollection
of the td
and th
elements of the row.
insertCell
( [ index ] )Creates a td
element, inserts it into the table row at the position given by the argument, and returns the td
.
The position is relative to the cells in the row. The index −1, which is the default if the argument is omitted, is equivalent to inserting at the end of the row.
If the given position is less than −1 or greater than the number of cells, throws an INDEX_SIZE_ERR
exception.
deleteCell
(index)Removes the td
or th
element with the given position in the row.
The position is relative to the cells in the row. The index −1 is equivalent to deleting the last cell of the row.
If the given position is less than −1 or greater than the index of the last cell, or if there are no cells, throws an INDEX_SIZE_ERR
exception.
td
elementtr
element.colspan
rowspan
headers
interface HTMLTableDataCellElement : HTMLTableCellElement {};
The td
element represents a data cell in a table.
th
elementtr
element.colspan
rowspan
headers
scope
interface HTMLTableHeaderCellElement : HTMLTableCellElement { attribute DOMString scope; };
The th
element represents a header cell in a table.
The th
element may have a scope
content attribute specified. The scope
attribute is an enumerated attribute with five states, four of which have explicit keywords:
row
keyword, which maps to the row statecol
keyword, which maps to the column staterowgroup
keyword, which maps to the row group stateth
element's scope
attribute must not be in the row group state if the element is not anchored in a row group.colgroup
keyword, which maps to the column group stateth
element's scope
attribute must not be in the column group state if the element is not anchored in a column group.The scope
attribute's missing value default is the auto state.
The scope
IDL attribute must reflect the content attribute of the same name, limited to only known values.
The following example shows how the scope
attribute's rowgroup
value affects which data cells a header cell applies to.
Here is a markup fragment showing a table:
<table> <thead> <tr> <th> ID <th> Measurement <th> Average <th> Maximum <tbody> <tr> <td> <th scope=rowgroup> Cats <td> <td> <tr> <td> 93 <th scope=row> Legs <td> 3.5 <td> 4 <tr> <td> 10 <th scope=row> Tails <td> 1 <td> 1 <tbody> <tr> <td> <th scope=rowgroup> English speakers <td> <td> <tr> <td> 32 <th scope=row> Legs <td> 2.67 <td> 4 <tr> <td> 35 <th scope=row> Tails <td> 0.33 <td> 1 </table>
This would result in the following table:
ID | Measurement | Average | Maximum |
---|---|---|---|
Cats | |||
93 | Legs | 3.5 | 4 |
10 | Tails | 1 | 1 |
English speakers | |||
32 | Legs | 2.67 | 4 |
35 | Tails | 0.33 | 1 |
The headers in the first row all apply directly down to the rows in their column.
The headers with the explicit scope
attributes apply to all the cells in their row group other than the cells in the first column.
The remaining headers apply just to the cells to the right of them.
td
and th
elementsThe td
and th
elements may have a colspan
content attribute specified, whose value must be a valid non-negative integer greater than zero.
The td
and th
elements may also have a rowspan
content attribute specified, whose value must be a valid non-negative integer.
These attributes give the number of columns and rows respectively that the cell is to span. These attributes must not be used to overlap cells.
The td
and th
element may have a headers
content attribute specified. The headers
attribute, if specified, must contain a string consisting of an unordered set of unique space-separated tokens that are case-sensitive, each of which must have the value of an ID of a th
element taking part in the same table as the td
or th
element.
A th
element with ID id is said to be directly targeted by all td
and th
elements in the same table that have headers
attributes whose values include as one of their tokens the ID id. A th
element A is said to be targeted by a th
or td
element B if either A is directly targeted by B or if there exists an element C that is itself targeted by the element B and A is directly targeted by C.
A th
element must not be targeted by itself.
The td
and th
elements implement interfaces that inherit from the HTMLTableCellElement
interface:
interface HTMLTableCellElement : HTMLElement { attribute unsigned long colSpan; attribute unsigned long rowSpan; [PutForwards=value] readonly attribute DOMSettableTokenList headers; readonly attribute long cellIndex; };
cellIndex
Returns the position of the cell in the row's cells
list. This does not necessarily correspond to the x-position of the cell in the table, since earlier cells might cover multiple rows or columns.
Returns 0 if the element isn't in a row.
The colSpan
IDL attribute must reflect the content attribute of the same name. The value must be limited to only non-negative numbers greater than zero.
The rowSpan
IDL attribute must reflect the content attribute of the same name. Its default value, which must be used if parsing the attribute as a non-negative integer returns an error, is 1.
The headers
IDL attribute must reflect the content attribute of the same name.
The following shows how might one mark up the bottom part of table 45 of the Smithsonian physical tables, Volume 71:
<table> <caption>Specification values: <b>Steel</b>, <b>Castings</b>, Ann. A.S.T.M. A27-16, Class B;* P max. 0.06; S max. 0.05.</caption> <thead> <tr> <th rowspan=2>Grade.</th> <th rowspan=2>Yield Point.</th> <th colspan=2>Ultimate tensile strength</th> <th rowspan=2>Per cent elong. 50.8mm or 2 in.</th> <th rowspan=2>Per cent reduct. area.</th> </tr> <tr> <th>kg/mm<sup>2</sup></th> <th>lb/in<sup>2</sup></th> </tr> </thead> <tbody> <tr> <td>Hard</td> <td>0.45 ultimate</td> <td>56.2</td> <td>80,000</td> <td>15</td> <td>20</td> </tr> <tr> <td>Medium</td> <td>0.45 ultimate</td> <td>49.2</td> <td>70,000</td> <td>18</td> <td>25</td> </tr> <tr> <td>Soft</td> <td>0.45 ultimate</td> <td>42.2</td> <td>60,000</td> <td>22</td> <td>30</td> </tr> </tbody> </table>
This table could look like this:
Grade. | Yield Point. | Ultimate tensile strength | Per cent elong. 50.8 mm or 2 in. | Per cent reduct. area. | |
---|---|---|---|---|---|
kg/mm2 | lb/in2 | ||||
Hard | 0.45 ultimate | 56.2 | 80,000 | 15 | 20 |
Medium | 0.45 ultimate | 49.2 | 70,000 | 18 | 25 |
Soft | 0.45 ultimate | 42.2 | 60,000 | 22 | 30 |
The following shows how one might mark up the gross margin table on page 46 of Apple, Inc's 10-K filing for fiscal year 2008:
<table> <thead> <tr> <th> <th>2008 <th>2007 <th>2006 <tbody> <tr> <th>Net sales <td>$ 32,479 <td>$ 24,006 <td>$ 19,315 <tr> <th>Cost of sales <td> 21,334 <td> 15,852 <td> 13,717 <tbody> <tr> <th>Gross margin <td>$ 11,145 <td>$ 8,154 <td>$ 5,598 <tfoot> <tr> <th>Gross margin percentage <td>34.3% <td>34.0% <td>29.0% </table>
The following shows how one might mark up the operating expenses table from lower on the same page of that document:
<table> <colgroup> <col> <colgroup> <col> <col> <col> <thead> <tr> <th> <th>2008 <th>2007 <th>2006 <tbody> <tr> <th scope=rowgroup> Research and development <td> $ 1,109 <td> $ 782 <td> $ 712 <tr> <th scope=row> Percentage of net sales <td> 3.4% <td> 3.3% <td> 3.7% <tbody> <tr> <th scope=rowgroup> Selling, general, and administrative <td> $ 3,761 <td> $ 2,963 <td> $ 2,433 <tr> <th scope=row> Percentage of net sales <td> 11.6% <td> 12.3% <td> 12.6% </table>
This table could look like this:
2008 | 2007 | 2006 | |
---|---|---|---|
Research and development | $ 1,109 | $ 782 | $ 712 |
Percentage of net sales | 3.4% | 3.3% | 3.7% |
Selling, general, and administrative | $ 3,761 | $ 2,963 | $ 2,433 |
Percentage of net sales | 11.6% | 12.3% | 12.6% |
A form is a component of a Web page that has form controls, such as text fields, buttons, checkboxes, range controls, or color pickers. A user can interact with such a form, providing data that can then be sent to the server for further processing (e.g. returning the results of a search or calculation). No client-side scripting is needed in many cases, though an API is available so that scripts can augment the user experience or use forms for purposes other than submitting data to a server.
Writing a form consists of several steps, which can be performed in any order: writing the user interface, implementing the server-side processing, and configuring the user interface to communicate with the server.
For the purposes of this brief introduction, we will create a pizza ordering form.
Any form starts with a form
element, inside which are placed the controls. Most controls are represented by the input
element, which by default provides a one-line text field. To label a control, the label
element is used; the label text and the control itself go inside the label
element. Each part of a form is considered a paragraph, and is typically separated from other parts using p
elements. Putting this together, here is how one might ask for the customer's name:
<form> <p><label>Customer name: <input></label></p> </form>
To let the user select the size of the pizza, we can use a set of radio buttons. Radio buttons also use the input
element, this time with a type
attribute with the value radio
. To make the radio buttons work as a group, they are given a common name using the name
attribute. To group a batch of controls together, such as, in this case, the radio buttons, one can use the fieldset
element. The title of such a group of controls is given by the first element in the fieldset
, which has to be a legend
element.
<form> <p><label>Customer name: <input></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size> Small </label></p> <p><label> <input type=radio name=size> Medium </label></p> <p><label> <input type=radio name=size> Large </label></p> </fieldset> </form>
Changes from the previous step are highlighted.
To pick toppings, we can use checkboxes. These use the input
element with a type
attribute with the value checkbox
:
<form> <p><label>Customer name: <input></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size> Small </label></p> <p><label> <input type=radio name=size> Medium </label></p> <p><label> <input type=radio name=size> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox> Bacon </label></p> <p><label> <input type=checkbox> Extra Cheese </label></p> <p><label> <input type=checkbox> Onion </label></p> <p><label> <input type=checkbox> Mushroom </label></p> </fieldset> </form>
The pizzeria for which this form is being written is always making mistakes, so it needs a way to contact the customer. For this purpose, we can use form controls specifically for telephone numbers (input
elements with their type
attribute set to tel
) and e-mail addresses (input
elements with their type
attribute set to email
):
<form> <p><label>Customer name: <input></label></p> <p><label>Telephone: <input type=tel></label></p> <p><label>E-mail address: <input type=email></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size> Small </label></p> <p><label> <input type=radio name=size> Medium </label></p> <p><label> <input type=radio name=size> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox> Bacon </label></p> <p><label> <input type=checkbox> Extra Cheese </label></p> <p><label> <input type=checkbox> Onion </label></p> <p><label> <input type=checkbox> Mushroom </label></p> </fieldset> </form>
We can use an input
element with its type
attribute set to time
to ask for a delivery time. Many of these form controls have attributes to control exactly what values can be specified; in this case, three attributes of particular interest are min
, max
, and step
. These set the minimum time, the maximum time, and the interval between allowed values (in seconds). This pizzeria only delivers between 11am and 9pm, and doesn't promise anything better than 15 minute increments, which we can mark up as follows:
<form> <p><label>Customer name: <input></label></p> <p><label>Telephone: <input type=tel></label></p> <p><label>E-mail address: <input type=email></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size> Small </label></p> <p><label> <input type=radio name=size> Medium </label></p> <p><label> <input type=radio name=size> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox> Bacon </label></p> <p><label> <input type=checkbox> Extra Cheese </label></p> <p><label> <input type=checkbox> Onion </label></p> <p><label> <input type=checkbox> Mushroom </label></p> </fieldset> <p><label>Preferred delivery time: <input type=time min="11:00" max="21:00" step="900"></label></p> </form>
The textarea
element can be used to provide a free-form text field. In this instance, we are going to use it to provide a space for the customer to give delivery instructions:
<form> <p><label>Customer name: <input></label></p> <p><label>Telephone: <input type=tel></label></p> <p><label>E-mail address: <input type=email></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size> Small </label></p> <p><label> <input type=radio name=size> Medium </label></p> <p><label> <input type=radio name=size> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox> Bacon </label></p> <p><label> <input type=checkbox> Extra Cheese </label></p> <p><label> <input type=checkbox> Onion </label></p> <p><label> <input type=checkbox> Mushroom </label></p> </fieldset> <p><label>Preferred delivery time: <input type=time min="11:00" max="21:00" step="900"></label></p> <p><label>Delivery instructions: <textarea></textarea></label></p> </form>
Finally, to make the form submittable we use the button
element:
<form> <p><label>Customer name: <input></label></p> <p><label>Telephone: <input type=tel></label></p> <p><label>E-mail address: <input type=email></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size> Small </label></p> <p><label> <input type=radio name=size> Medium </label></p> <p><label> <input type=radio name=size> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox> Bacon </label></p> <p><label> <input type=checkbox> Extra Cheese </label></p> <p><label> <input type=checkbox> Onion </label></p> <p><label> <input type=checkbox> Mushroom </label></p> </fieldset> <p><label>Preferred delivery time: <input type=time min="11:00" max="21:00" step="900"></label></p> <p><label>Delivery instructions: <textarea></textarea></label></p> <p><button>Submit order</button></p> </form>
The exact details for writing a server-side processor are out of scope for this specification. For the purposes of this introduction, we will assume that the script at https://pizza.example.com/order.cgi
is configured to accept submissions using the application/x-www-form-urlencoded
format, expecting the following parameters sent in an HTTP POST body:
custname
custtel
custemail
size
small
, medium
, or large
toppings
bacon
, cheese
, onion
, and mushroom
delivery
comments
Form submissions are exposed to servers in a variety of ways, most commonly as HTTP GET or POST requests. To specify the exact method used, the method
attribute is specified on the form
element. This doesn't specify how the form data is encoded, though; to specify that, you use the enctype
attribute. You also have to specify the URL of the service that will handle the submitted data, using the action
attribute.
For each form control you want submitted, you then have to give a name that will be used to refer to the data in the submission. We already specified the name for the group of radio buttons; the same attribute (name
) also specifies the submission name. Radio buttons can be distinguished from each other in the submission by giving them different values, using the value
attribute.
Multiple controls can have the same name; for example, here we give all the checkboxes the same name, and the server distinguishes which checkbox was checked by seeing which values are submitted with that name — like the radio buttons, they are also given unique values with the value
attribute.
Given the settings in the previous section, this all becomes:
<form method="post" enctype="application/x-www-form-urlencoded" action="https://pizza.example.com/order.cgi"> <p><label>Customer name: <input name="custname"></label></p> <p><label>Telephone: <input type=tel name="custtel"></label></p> <p><label>E-mail address: <input type=email name="custemail"></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size value="small"> Small </label></p> <p><label> <input type=radio name=size value="medium"> Medium </label></p> <p><label> <input type=radio name=size value="large"> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox name="topping" value="bacon"> Bacon </label></p> <p><label> <input type=checkbox name="topping" value="cheese"> Extra Cheese </label></p> <p><label> <input type=checkbox name="topping" value="onion"> Onion </label></p> <p><label> <input type=checkbox name="topping" value="mushroom"> Mushroom </label></p> </fieldset> <p><label>Preferred delivery time: <input type=time min="11:00" max="21:00" step="900" name="delivery"></label></p> <p><label>Delivery instructions: <textarea name="comments"></textarea></label></p> <p><button>Submit order</button><p> </form>
For example, if the customer entered "Denise Lawrence" as their name, "555-321-8642" as their telephone number, did not specify an e-mail address, asked for a medium-sized pizza, selected the Extra Cheese and Mushroom toppings, entered a delivery time of 7pm, and left the delivery instructions text field blank, the user agent would submit the following to the online Web service:
custname=Denise+Lawrence&custtel=555-321-8624&custemail=&size=medium&topping=cheese&topping=mushroom&delivery=19%3A00&comments=
Forms can be annotated in such a way that the user agent will check the user's input before the form is submitted. The server still has to verify the input is valid (since hostile users can easily bypass the form validation), but it allows the user to avoid the wait incurred by having the server be the sole checker of the user's input.
The simplest annotation is the required
attribute, which can be specified on input
elements to indicate that the form is not to be submitted until a value is given. By adding this attribute to the customer name and delivery time fields, we allow the user agent to notify the user when the user submits the form without filling in those fields:
<form method="post" enctype="application/x-www-form-urlencoded" action="https://pizza.example.com/order.cgi"> <p><label>Customer name: <input name="custname" required></label></p> <p><label>Telephone: <input type=tel name="custtel"></label></p> <p><label>E-mail address: <input type=email name="custemail"></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size value="small"> Small </label></p> <p><label> <input type=radio name=size value="medium"> Medium </label></p> <p><label> <input type=radio name=size value="large"> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox name="topping" value="bacon"> Bacon </label></p> <p><label> <input type=checkbox name="topping" value="cheese"> Extra Cheese </label></p> <p><label> <input type=checkbox name="topping" value="onion"> Onion </label></p> <p><label> <input type=checkbox name="topping" value="mushroom"> Mushroom </label></p> </fieldset> <p><label>Preferred delivery time: <input type=time min="11:00" max="21:00" step="900" name="delivery" required></label></p> <p><label>Delivery instructions: <textarea name="comments"></textarea></label></p> <p><button>Submit order</button><p> </form>
It is also possible to limit the length of the input, using the maxlength
attribute. By adding this to the textarea
element, we can limit users to 1000 characters, preventing them from writing huge essays to the busy delivery drivers instead of staying focused and to the point:
<form method="post" enctype="application/x-www-form-urlencoded" action="https://pizza.example.com/order.cgi"> <p><label>Customer name: <input name="custname" required></label></p> <p><label>Telephone: <input type=tel name="custtel"></label></p> <p><label>E-mail address: <input type=email name="custemail"></label></p> <fieldset> <legend> Pizza Size </legend> <p><label> <input type=radio name=size value="small"> Small </label></p> <p><label> <input type=radio name=size value="medium"> Medium </label></p> <p><label> <input type=radio name=size value="large"> Large </label></p> </fieldset> <fieldset> <legend> Pizza Toppings </legend> <p><label> <input type=checkbox name="topping" value="bacon"> Bacon </label></p> <p><label> <input type=checkbox name="topping" value="cheese"> Extra Cheese </label></p> <p><label> <input type=checkbox name="topping" value="onion"> Onion </label></p> <p><label> <input type=checkbox name="topping" value="mushroom"> Mushroom </label></p> </fieldset> <p><label>Preferred delivery time: <input type=time min="11:00" max="21:00" step="900" name="delivery" required></label></p> <p><label>Delivery instructions: <textarea name="comments" maxlength=1000></textarea></label></p> <p><button>Submit order</button><p> </form>
Mostly for historical reasons, elements in this section fall into several overlapping (but subtly different) categories in addition to the usual ones like flow content, phrasing content, and interactive content.
A number of the elements are form-associated elements, which means they can have a form owner and, to expose this, have a form
content attribute with a matching form
IDL attribute.
The form-associated elements fall into several subcategories:
Denotes elements that are listed in the form.elements
and fieldset.elements
APIs.
Denotes elements that can be associated with label
elements.
Denotes elements that can be used for constructing the form data set when a form
element is submitted.
Denotes elements that can be affected when a form
element is reset.
In addition, some submittable elements can be, depending on their attributes, buttons. The prose below defines when an element is a button. Some buttons are specifically submit buttons.
The object
element is also a form-associated element and can, with the use of a suitable plugin, partake in form submission.
form
elementform
element descendants.accept-charset
action
autocomplete
enctype
method
name
novalidate
target
[OverrideBuiltins] interface HTMLFormElement : HTMLElement { attribute DOMString acceptCharset; attribute DOMString action; attribute DOMString autocomplete; attribute DOMString enctype; attribute DOMString encoding; attribute DOMString method; attribute DOMString name; attribute boolean noValidate; attribute DOMString target; readonly attribute HTMLFormControlsCollection elements; readonly attribute long length; caller getter any (in unsigned long index); caller getter any (in DOMString name); void submit(); void reset(); boolean checkValidity(); };
The form
element represents a collection of form-associated elements, some of which can represent editable values that can be submitted to a server for processing.
The accept-charset
attribute gives the character encodings that are to be used for the submission. If specified, the value must be an ordered set of unique space-separated tokens that are ASCII case-insensitive, and each token must be an ASCII case-insensitive match for the preferred MIME name of an ASCII-compatible character encoding. [IANACHARSET]
The name
attribute represents the form
's name within the forms
collection. The value must not be the empty string, and the value must be unique amongst the form
elements in the forms
collection that it is in, if any.
The autocomplete
attribute is an enumerated attribute. The attribute has two states. The on
keyword maps to the on state, and the off
keyword maps to the off state. The attribute may also be omitted. The missing value default is the on state. The off state indicates that by
default, input
elements in the form will have their resulting autocompletion state set to off; the on state indicates that by default, input
elements in the form will have their resulting autocompletion state set to on.
The action
, enctype
, method
, novalidate
, and target
attributes are attributes for form submission.
elements
Returns an HTMLCollection
of the form controls in the form (excluding image buttons for historical reasons).
length
Returns the number of form controls in the form (excluding image buttons for historical reasons).
Returns the indexth element in the form (excluding image buttons for historical reasons).
Returns the form control in the form with the given ID or name
(excluding image buttons for historical reasons).
Once an element has been referenced using a particular name, that name will continue being available as a way to reference that element in this method, even if the element's actual ID or name
changes, for as long as the element remains in the Document
.
If there are multiple matching items, then a NodeList
object containing all those elements is returned.
Returns null if no element with that ID or name
could be found.
submit
()Submits the form.
reset
()Resets the form.
checkValidity
()Returns true if the form's controls are all valid; otherwise, returns false.
The autocomplete
IDL attribute must reflect the content attribute of the same name, limited to only known values.
The name
IDL attribute must reflect the content attribute of the same name.
The acceptCharset
IDL attribute must reflect the accept-charset
content attribute.
This example shows two search forms:
<form action="http://www.google.com/search" method="get"> <label>Google: <input type="search" name="q"></label> <input type="submit" value="Search..."> </form> <form action="http://www.bing.com/search" method="get"> <label>Bing: <input type="search" name="q"></label> <input type="submit" value="Search..."> </form>
fieldset
elementlegend
element, followed by flow content.disabled
form
name
interface HTMLFieldSetElement : HTMLElement { attribute boolean disabled; readonly attribute HTMLFormElement form; attribute DOMString name; readonly attribute DOMString type; readonly attribute HTMLFormControlsCollection elements; readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); };
The fieldset
element represents a set of form controls optionally grouped under a common name.
The name of the group is given by the first legend
element that is a child of the fieldset
element, if any. The remainder of the descendants form the group.
The disabled
attribute, when specified, causes all the form control descendants of the fieldset
element, excluding those that are descendants of the fieldset
element's first legend
element child, if any, to be disabled.
The form
attribute is used to explicitly associate the fieldset
element with its form owner. The name
attribute represents the element's name.
type
Returns the string "fieldset".
elements
Returns an HTMLFormControlsCollection
of the form controls in the element.
The disabled
IDL attribute must reflect the content attribute of the same name.
The following snippet shows a fieldset with a checkbox in the legend that controls whether or not the fieldset is enabled. The contents of the fieldset consist of two required text fields and an optional year/month control.
<fieldset name="clubfields" disabled> <legend> <label> <input type=checkbox name=club onchange="form.clubfields.disabled = !checked"> Use Club Card </label> </legend> <p><label>Name on card: <input name=clubname required></label></p> <p><label>Card number: <input name=clubnum required pattern="[-0-9]+"></label></p> <p><label>Expiry date: <input name=clubexp type=month></label></p> </fieldset>
You can also nest fieldset
elements. Here is an example expanding on the previous one that does so:
<fieldset name="clubfields" disabled> <legend> <label> <input type=checkbox name=club onchange="form.clubfields.disabled = !checked"> Use Club Card </label> </legend> <p><label>Name on card: <input name=clubname required></label></p> <fieldset name="numfields"> <legend> <label> <input type=radio checked name=clubtype onchange="form.numfields.disabled = !checked"> My card has numbers on it </label> </legend> <p><label>Card number: <input name=clubnum required pattern="[-0-9]+"></label></p> </fieldset> <fieldset name="letfields" disabled> <legend> <label> <input type=radio name=clubtype onchange="form.letfields.disabled = !checked"> My card has letters on it </label> </legend> <p><label>Card code: <input name=clublet required pattern="[A-Za-z]+"></label></p> </fieldset> </fieldset>
In this example, if the outer "Use Club Card" checkbox is not checked, everything inside the outer fieldset
, including the two radio buttons in the legends of the two nested fieldset
s, will be disabled. However, if the checkbox is checked, then the radio buttons will both be enabled and will let you select which of the two inner fieldset
s is to be enabled.
legend
elementfieldset
element.interface HTMLLegendElement : HTMLElement { readonly attribute HTMLFormElement form; };
The legend
element represents a caption for the rest of the contents of the legend
element's parent fieldset
element.
form
Returns the element's form
element, if any, or null otherwise.
label
elementlabel
elements.form
for
interface HTMLLabelElement : HTMLElement { readonly attribute HTMLFormElement form; attribute DOMString htmlFor; readonly attribute HTMLElement control; };
The label
represents a caption in a user interface. The caption can be associated with a specific form control, either using for
attribute, or by putting the form control inside the label
element itself.
The for
attribute may be specified to indicate a form control with which the caption is to be associated. If the attribute is specified, the attribute's value must be the ID of a labelable form-associated element in the same Document
as the label
element.
control
Returns the form control that is associated with this element.
The form
attribute is used to explicitly associate the label
element with its form owner.
The htmlFor
IDL attribute must reflect the for
content attribute.
labels
Returns a NodeList
of all the label
elements that the form control is associated with.
The following example shows three form controls each with a label, two of which have small text showing the right format for users to use.
<p><label>Full name: <input name=fn> <small>Format: First Last</small></label></p> <p><label>Age: <input name=age type=number min=0></label></p> <p><label>Post code: <input name=pc> <small>Format: AB12 3CD</small></label></p>
input
elementtype
attribute is not in the Hidden state: Interactive content.type
attribute is not in the Hidden state: Listed, labelable, submittable, and resettable form-associated element.type
attribute is in the Hidden state: Listed, submittable, and resettable form-associated element.accept
alt
autocomplete
autofocus
checked
dirname
disabled
form
formaction
formenctype
formmethod
formnovalidate
formtarget
height
list
max
maxlength
min
multiple
name
pattern
placeholder
readonly
required
size
src
step
type
value
width
interface HTMLInputElement : HTMLElement { attribute DOMString accept; attribute DOMString alt; attribute DOMString autocomplete; attribute boolean autofocus; attribute boolean defaultChecked; attribute boolean checked; attribute DOMString dirName; attribute boolean disabled; readonly attribute HTMLFormElement form; readonly attribute FileList files; attribute DOMString formAction; attribute DOMString formEnctype; attribute DOMString formMethod; attribute boolean formNoValidate; attribute DOMString formTarget; attribute DOMString height; attribute boolean indeterminate; readonly attribute HTMLElement list; attribute DOMString max; attribute long maxLength; attribute DOMString min; attribute boolean multiple; attribute DOMString name; attribute DOMString pattern; attribute DOMString placeholder; attribute boolean readOnly; attribute boolean required; attribute unsigned long size; attribute DOMString src; attribute DOMString step; attribute DOMString type; attribute DOMString defaultValue; attribute DOMString value; attribute Date valueAsDate; attribute double valueAsNumber; readonly attribute HTMLOptionElement selectedOption; attribute DOMString width; void stepUp(in optional long n); void stepDown(in optional long n); readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); readonly attribute NodeList labels; void select(); attribute unsigned long selectionStart; attribute unsigned long selectionEnd; attribute DOMString selectionDirection; void setSelectionRange(in unsigned long start, in unsigned long end, in optional DOMString direction); };
The input
element represents a typed data field, usually with a form control to allow the user to edit the data.
The type
attribute controls the data type (and associated control) of the element. It is an enumerated attribute. The following table lists the keywords and states for the attribute — the keywords in the left column map to the states in the cell in the second column on the same row as the keyword.
Keyword | State | Data type | Control type |
---|---|---|---|
hidden |
An arbitrary string | n/a | |
text |
Text | Text with no line breaks | Text field |
search |
Search | Text with no line breaks | Search field |
tel |
Telephone | Text with no line breaks | A text field |
url |
URL | An absolute IRI | A text field |
email |
An e-mail address or list of e-mail addresses | A text field | |
password |
Password | Text with no line breaks (sensitive information) | Text field that obscures data entry |
datetime |
Date and Time | A date and time (year, month, day, hour, minute, second, fraction of a second) with the time zone set to UTC | A date and time control |
date |
Date | A date (year, month, day) with no time zone | A date control |
month |
Month | A date consisting of a year and a month with no time zone | A month control |
week |
Week | A date consisting of a week-year number and a week number with no time zone | A week control |
time |
Time | A time (hour, minute, seconds, fractional seconds) with no time zone | A time control |
datetime-local |
Local Date and Time | A date and time (year, month, day, hour, minute, second, fraction of a second) with no time zone | A date and time control |
number |
Number | A numerical value | A text field or spinner control |
range |
Range | A numerical value, with the extra semantic that the exact value is not important | A slider control or similar |
color |
Color | An sRGB color with 8-bit red, green, and blue components | A color well |
checkbox |
Checkbox | A set of zero or more values from a predefined list | A checkbox |
radio |
Radio Button | An enumerated value | A radio button |
file |
File Upload | Zero or more files each with a MIME type and optionally a file name | A label and a button |
submit |
Submit Button | An enumerated value, with the extra semantic that it must be the last value selected and initiates form submission | A button |
image |
Image Button | A coordinate, relative to a particular image's size, with the extra semantic that it must be the last value selected and initiates form submission | Either a clickable image, or a button |
reset |
Reset Button | n/a | A button |
button |
Button | n/a | A button |
The missing value default is the Text state.
Which of the accept
, alt
, autocomplete
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, maxlength
, min
, multiple
, pattern
, placeholder
, readonly
, required
, size
, src
, step
, and width
content attributes, the checked
, files
, valueAsDate
, valueAsNumber
, list
, and selectedOption
IDL attributes, the select()
method, the selectionStart
, selectionEnd
, and selectionDirection
, IDL attributes, the setSelectionRange()
method, the stepUp()
and stepDown()
methods, and the input
and change
events apply to an input
element depends on the state of its type
attribute. The following table summarizes which of those content attributes, IDL attributes, methods, and events apply to each state:
Text, Search | URL, Telephone | Password | Date and Time, Date, Month, Week, Time | Local Date and Time, Number | Range | Color | Checkbox, Radio Button | File Upload | Submit Button | Image Button | Reset Button, Button | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Content attributes | ||||||||||||||
accept |
· | · | · | · | · | · | · | · | · | · | Yes | · | · | · |
alt |
· | · | · | · | · | · | · | · | · | · | · | · | Yes | · |
autocomplete |
· | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | · | · | · | · | · |
checked |
· | · | · | · | · | · | · | · | · | Yes | · | · | · | · |
dirname |
· | Yes | · | · | · | · | · | · | · | · | · | · | · | · |
formaction |
· | · | · | · | · | · | · | · | · | · | · | Yes | Yes | · |
formenctype |
· | · | · | · | · | · | · | · | · | · | · | Yes | Yes | · |
formmethod |
· | · | · | · | · | · | · | · | · | · | · | Yes | Yes | · |
formnovalidate |
· | · | · | · | · | · | · | · | · | · | · | Yes | Yes | · |
formtarget |
· | · | · | · | · | · | · | · | · | · | · | Yes | Yes | · |
height |
· | · | · | · | · | · | · | · | · | · | · | · | Yes | · |
list |
· | Yes | Yes | Yes | · | Yes | Yes | Yes | Yes | · | · | · | · | · |
max |
· | · | · | · | · | Yes | Yes | Yes | · | · | · | · | · | · |
maxlength |
· | Yes | Yes | Yes | Yes | · | · | · | · | · | · | · | · | · |
min |
· | · | · | · | · | Yes | Yes | Yes | · | · | · | · | · | · |
multiple |
· | · | · | Yes | · | · | · | · | · | · | Yes | · | · | · |
pattern |
· | Yes | Yes | Yes | Yes | · | · | · | · | · | · | · | · | · |
placeholder |
· | Yes | Yes | Yes | Yes | · | · | · | · | · | · | · | · | · |
readonly |
· | Yes | Yes | Yes | Yes | Yes | Yes | · | · | · | · | · | · | · |
required |
· | Yes | Yes | Yes | Yes | Yes | Yes | · | · | Yes | Yes | · | · | · |
size |
· | Yes | Yes | Yes | Yes | · | · | · | · | · | · | · | · | · |
src |
· | · | · | · | · | · | · | · | · | · | · | · | Yes | · |
step |
· | · | · | · | · | Yes | Yes | Yes | · | · | · | · | · | · |
width |
· | · | · | · | · | · | · | · | · | · | · | · | Yes | · |
IDL attributes and methods | ||||||||||||||
checked |
· | · | · | · | · | · | · | · | · | Yes | · | · | · | · |
files |
· | · | · | · | · | · | · | · | · | · | Yes | · | · | · |
valueAsDate |
· | · | · | · | · | Yes | · | · | · | · | · | · | · | · |
valueAsNumber |
· | · | · | · | · | Yes | Yes | Yes | · | · | · | · | · | · |
list |
· | Yes | Yes | Yes | · | Yes | Yes | Yes | Yes | · | · | · | · | · |
selectedOption |
· | Yes | Yes | Yes† | · | Yes | Yes | Yes | Yes | · | · | · | · | · |
select() |
· | Yes | Yes | · | Yes | · | · | · | · | · | · | · | · | · |
selectionStart |
· | Yes | Yes | · | Yes | · | · | · | · | · | · | · | · | · |
selectionEnd |
· | Yes | Yes | · | Yes | · | · | · | · | · | · | · | · | · |
selectionDirection |
· | Yes | Yes | · | Yes | · | · | · | · | · | · | · | · | · |
setSelectionRange() |
· | Yes | Yes | · | Yes | · | · | · | · | · | · | · | · | · |
stepDown() |
· | · | · | · | · | Yes | Yes | Yes | · | · | · | · | · | · |
stepUp() |
· | · | · | · | · | Yes | Yes | Yes | · | · | · | · | · | · |
Events | ||||||||||||||
input event |
· | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | · | · | · | · | · |
change event |
· | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | · | · | · |
† The dagger symbol (†) indicates that the feature only applies when the multiple
attribute is not specified.
The value
content attribute gives the default value of the input
element.
The checked
content attribute is a boolean attribute that gives the default checkedness of the input
element.
The form
attribute is used to explicitly associate the input
element with its form owner. The name
attribute represents the element's name. The disabled
attribute is used to make the control non-interactive and to prevent its value from being submitted. The autofocus
attribute controls focus.
The indeterminate
IDL attribute must initially be set to false. On getting, it must return the last value it was set to. On setting, it must be set to the new value. It has no effect except for changing the appearance of checkbox controls.
The accept
, alt
, max
, min
, multiple
, pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.
The autocomplete
and type
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative numbers.
type
attributeThe input
element represents a value that is not intended to be examined or manipulated by the user.
If the name
attribute is present and has a value that is a case-sensitive match for the string "_charset_
", then the element's value
attribute must be omitted.
The value
IDL attribute applies to this element and is in mode default.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, autocomplete
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, maxlength
, min
, multiple
,
pattern
, placeholder
, readonly
, required
, size
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
,
setSelectionRange()
, stepDown()
, and stepUp()
methods.
The input
element represents a one line plain text edit control for the element's value.
The difference between the Text state and the Search state is primarily stylistic: on platforms where search fields are distinguished from regular text fields, the Search state might result in an appearance consistent with the platform's search fields rather than appearing like a regular text field.
The value
attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, dirname
, list
, maxlength
, pattern
, placeholder
, readonly
, required
, and
size
content attributes; list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, and value
IDL attributes; select()
and setSelectionRange()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, max
, min
, multiple
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, valueAsDate
, and valueAsNumber
IDL attributes; stepDown()
and stepUp()
methods.
The input
element represents a control for editing a telephone number given in the element's value.
The value
attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters.
Unlike the URL and E-mail types, the Telephone type does not enforce a particular syntax. This is intentional; in practice, telephone number fields tend to be free-form fields, because there are a wide variety of valid phone numbers. Systems that need to enforce a particular format are encouraged to use the pattern
attribute or the setCustomValidity()
method to hook into the client-side validation mechanism.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, maxlength
, pattern
, placeholder
, readonly
, required
, and size
content
attributes; list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, and value
IDL attributes; select()
and setSelectionRange()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, max
, min
, multiple
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, valueAsDate
, and valueAsNumber
IDL attributes; stepDown()
and stepUp()
methods.
The input
element represents a control for editing a single absolute URL given in the element's value.
The value
attribute, if specified and not empty, must have a value that is a valid URL potentially surrounded by spaces that is also an absolute URL.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, maxlength
, pattern
, placeholder
, readonly
, required
, and size
content
attributes; list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, and value
IDL attributes; select()
and setSelectionRange()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, max
, min
, multiple
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, valueAsDate
, and valueAsNumber
IDL attributes; stepDown()
and stepUp()
methods.
If a document contained the following markup:
<input type="url" name="location" list="urls"> <datalist id="urls"> <option label="MIME: Format of Internet Message Bodies" value="http://tools.ietf.org/html/rfc2045"> <option label="HTML 4.01 Specification" value="http://www.w3.org/TR/html4/"> <option label="Form Controls" value="http://www.w3.org/TR/xforms/slice8.html#ui-commonelems-hint"> <option label="Scalable Vector Graphics (SVG) 1.1 Specification" value="http://www.w3.org/TR/SVG/"> <option label="Feature Sets - SVG 1.1 - 20030114" value="http://www.w3.org/TR/SVG/feature.html"> <option label="The Single UNIX Specification, Version 3" value="http://www.unix-systems.org/version3/"> </datalist>
...and the user had typed "www.w3", and the user agent had also found that the user had visited http://www.w3.org/Consortium/#membership
and http://www.w3.org/TR/XForms/
in the recent past, then the rendering might look like this:
The first four URLs in this sample consist of the four URLs in the author-specified list that match the text the user has entered, sorted in some UA-defined manner (maybe by how frequently the user refers to those URLs). Note how the UA is using the knowledge that the values are URLs to allow the user to omit the scheme part and perform intelligent matching on the domain name.
The last two URLs (and probably many more, given the scrollbar's indications of more values being available) are the matches from the user agent's session history data. This data is not made available to the page DOM. In this particular case, the UA has no titles to provide for those values.
How the E-mail state operates depends on whether the multiple
attribute is specified or not.
multiple
attribute is not specified on the elementThe input
element represents a control for editing an e-mail address given in the element's value.
The value
attribute, if specified and not empty, must have a value that is a single valid e-mail address.
multiple
attribute is specified on the elementThe input
element represents a control for adding, removing, and editing the e-mail addresses given in the element's values.
The value
attribute, if specified, must have a value that is a valid e-mail address list.
A valid e-mail address is a string that matches the ABNF production 1*( atext / "." ) "@" ldh-str *( "." ldh-str )
where atext
is defined in RFC 5322 section 3.2.3, and ldh-str
is defined in RFC 1034 section 3.5. [ABNF] [RFC5322] [RFC1034]
This requirement is a willful violation of RFC 5322, which defines a syntax for e-mail addresses that is simultaneously too strict (before the "@" character), too vague (after the "@" character), and too lax (allowing comments, white space characters, and quoted strings in manners unfamiliar to most users) to be of practical use here.
A valid e-mail address list is a set of comma-separated tokens, where each token is itself a valid e-mail address.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, maxlength
, multiple
, pattern
, placeholder
, readonly
, required
,
and size
content attributes; list
and value
IDL attributes.
The following common input
element content attributes, IDL attributes, and methods apply to the element when the multiple
attribute is not specified: selectedOption
IDL attribute.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, max
, min
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
, setSelectionRange()
, stepDown()
and stepUp()
methods.
The input
element represents a one line plain text edit control for the element's value. The user agent should obscure the value so that people other than the user cannot see it.
The value
attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, maxlength
, pattern
, placeholder
, readonly
, required
, and size
content attributes; selectionStart
, selectionEnd
, selectionDirection
, and value
IDL attributes; select()
, and setSelectionRange()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, min
, multiple
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, list
, selectedOption
, valueAsDate
, and valueAsNumber
IDL attributes; stepDown()
and stepUp()
methods.
The input
element represents a control for setting the element's value to a string representing a specific global date and time.
The format shown to the user is independent of the format used for form submission. Browsers are encouraged to use user interfaces that present dates and times according to the conventions of the user's preferred locale.
The value
attribute, if specified and not empty, must have a value that is a valid global date and time string.
The min
attribute, if specified, must have a value that is a valid global date and time string. The max
attribute, if specified, must have a value that is a valid global date and time string.
The step
attribute is expressed in seconds. The default step is 60 seconds.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, readonly
, required
, and step
content attributes; list
, value
, valueAsDate
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, and selectionDirection
IDL attributes; select()
and setSelectionRange()
methods.
The following fragment shows part of a calendar application. A user can specify a date and time for a meeting (in his local time zone, probably, though the user agent can allow the user to change that), and since the submitted data includes the time-zone offset, the application can ensure that the meeting is shown at the correct time regardless of the time zones used by all the participants.
<fieldset> <legend>Add Meeting</legend> <p><label>Meeting name: <input type=text name="meeting.label"></label> <p><label>Meeting time: <input type=datetime name="meeting.start"></label> </fieldset>
Had the application used the datetime-local
type instead, the calendar application would have also had to explicitly determine which time zone the user intended.
The input
element represents a control for setting the element's value to a string representing a specific date.
The format shown to the user is independent of the format used for form submission. Browsers are encouraged to use user interfaces that present dates according to the conventions of the user's preferred locale.
The value
attribute, if specified and not empty, must have a value that is a valid date string.
The min
attribute, if specified, must have a value that is a valid date string. The max
attribute, if specified, must have a value that is a valid date string.
The step
attribute is expressed in days. The default step is 1 day.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, readonly
, required
, and step
content attributes; list
, value
, valueAsDate
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, selectionStart
, selectionEnd
, and selectionDirection
IDL attributes; select()
and setSelectionRange()
methods.
The input
element represents a control for setting the element's value to a string representing a specific month.
The format shown to the user is independent of the format used for form submission. Browsers are encouraged to use user interfaces that present months according to the conventions of the user's preferred locale.
The value
attribute, if specified and not empty, must have a value that is a valid month string.
The min
attribute, if specified, must have a value that is a valid month string. The max
attribute, if specified, must have a value that is a valid month string.
The step
attribute is expressed in months. The default step is 1 month.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, readonly
, required
, and step
content attributes; list
, value
, valueAsDate
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, and selectionDirection
IDL attributes; select()
and setSelectionRange()
methods.
The input
element represents a control for setting the element's value to a string representing a specific week.
The format shown to the user is independent of the format used for form submission. Browsers are encouraged to use user interfaces that present weeks according to the conventions of the user's preferred locale.
The value
attribute, if specified and not empty, must have a value that is a valid week string.
The min
attribute, if specified, must have a value that is a valid week string. The max
attribute, if specified, must have a value that is a valid week string.
The step
attribute is expressed in weeks. The default step is 1 week.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, readonly
, required
, and step
content attributes; list
, value
, valueAsDate
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, and selectionDirection
IDL attributes; select()
and setSelectionRange()
methods.
The input
element represents a control for setting the element's value to a string representing a specific time.
The format shown to the user is independent of the format used for form submission. Browsers are encouraged to use user interfaces that present times according to the conventions of the user's preferred locale.
The value
attribute, if specified and not empty, must have a value that is a valid time string.
The min
attribute, if specified, must have a value that is a valid time string. The max
attribute, if specified, must have a value that is a valid time string.
The step
attribute is expressed in seconds. The default step is 60 seconds.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, readonly
, required
, and step
content attributes; list
, value
, valueAsDate
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, and selectionDirection
IDL attributes; select()
and setSelectionRange()
methods.
The input
element represents a control for setting the element's value to a string representing a local date and time, with no time-zone offset information.
The format shown to the user is independent of the format used for form submission. Browsers are encouraged to use user interfaces that present dates and times according to the conventions of the user's preferred locale.
The value
attribute, if specified and not empty, must have a value that is a valid local date and time string.
The min
attribute, if specified, must have a value that is a valid local date and time string. The max
attribute, if specified, must have a value that is a valid local date and time string.
The step
attribute is expressed in seconds. The default step is 60 seconds.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, readonly
, required
, and step
content attributes; list
, value
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, selectionDirection
, and valueAsDate
IDL attributes; select()
and setSelectionRange()
methods.
The following example shows part of a flight booking application. The application uses an input
element with its type
attribute set to datetime-local
, and it then interprets the given date and time in the time zone of the selected airport.
<fieldset> <legend>Destination</legend> <p><label>Airport: <input type=text name=to list=airports></label></p> <p><label>Departure time: <input type=datetime-local name=totime step=3600></label></p> </fieldset> <datalist id=airports> <option value=ATL label="Atlanta"> <option value=MEM label="Memphis"> <option value=LHR label="London Heathrow"> <option value=LAX label="Los Angeles"> <option value=FRA label="Frankfurt"> </datalist>
If the application instead used the datetime
type, then the user would have to work out the time-zone conversions himself, which is clearly not a good user experience!
The input
element represents a control for setting the element's value to a string representing a number.
The value
attribute, if specified and not empty, must have a value that is a valid floating point number.
The min
attribute, if specified, must have a value that is a valid floating point number. The max
attribute, if specified, must have a value that is a valid floating point number.
The default step is 1 (allowing only integers, unless the min
attribute has a non-integer value).
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, readonly
, required
, and step
content attributes; list
, value
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, selectionDirection
, and valueAsDate
IDL attributes; select()
and setSelectionRange()
methods.
The input
element represents a control for setting the element's value to a string representing a number, but with the caveat that the exact value is not important, letting UAs provide a simpler interface than they do for the Number state.
The value
attribute, if specified, must have a value that is a valid floating point number.
The min
attribute, if specified, must have a value that is a valid floating point number. The default minimum is 0. The max
attribute, if specified, must have a value that is a valid floating point number. The default maximum is 100.
The default value is the minimum plus half the difference between the minimum and the maximum, unless the maximum is less than the minimum, in which case the default value is the minimum.
The default step is 1 (allowing only integers, unless the min
attribute has a non-integer value).
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
, list
, max
, min
, and step
content attributes; list
, value
, valueAsNumber
, and selectedOption
IDL attributes; stepDown()
and stepUp()
methods.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, multiple
, pattern
, placeholder
, readonly
, required
, size
, src
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, selectionDirection
, and valueAsDate
IDL attributes; select()
and setSelectionRange()
methods.
Here is an example of a range control using an autocomplete list with the list
attribute. This could be useful if there are values along the full range of the control that are especially important, such as preconfigured light levels or typical speed limits in a range control used as a speed control. The following markup fragment:
<input type="range" min="-100" max="100" value="0" step="10" name="power" list="powers"> <datalist id="powers"> <option value="0"> <option value="-30"> <option value="30"> <option value="+50"> </datalist>
...with the following style sheet applied:
input { height: 75px; width: 49px; background: #D5CCBB; color: black; }
...might render as:
Note how the UA determined the orientation of the control from the ratio of the style-sheet-specified height and width properties. The colors were similiarly derived from the style sheet. The tick marks, however, were derived from the markup. In particular, the step
attribute has not affected the placement of tick marks, the UA deciding to only use the author-specified completion values and then adding longer tick marks at the extremes.
Note also how the invalid value +50
was completely ignored.
For another example, consider the following markup fragment:
<input name=x type=range min=100 max=700 step=9.09090909 value=509.090909>
A user agent could display in a variety of ways, for instance:
Or, alternatively, for instance:
The user agent could pick which one to display based on the dimensions given in the style sheet. This would allow it to maintain the same resolution for the tick marks, despite the differences in width.
The input
element represents a color well control, for setting the element's value to a string representing a simple color.
The value
attribute, if specified and not empty, must have a value that is a valid simple color.
The following common input
element content attributes, IDL attributes, and methods apply to the element: autocomplete
and list
content attributes; list
, value
, and selectedOption
IDL attributes.
The value
IDL attribute is in mode value.
The input
and change
events apply.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, maxlength
, max
, min
, multiple
, pattern
, placeholder
, readonly
, required
, size
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
, setSelectionRange()
, stepDown()
, and stepUp()
methods.
The input
element represents a two-state control that represents the element's checkedness state. If the element's checkedness state is true, the control represents a positive selection, and if it is false, a negative selection. If the element's indeterminate
IDL attribute is set to true, then the control's selection should be obscured as if the control was in a third, indeterminate, state.
The control is never a true tri-state control, even if the element's indeterminate
IDL attribute is set to true. The indeterminate
IDL attribute only gives the appearance of a third state.
indeterminate
[ = value ]When set, overrides the rendering of checkbox controls so that the current value is not visible.
The following common input
element content attributes and IDL attributes apply to the element: checked
, and required
content attributes; checked
and value
IDL attributes.
The value
IDL attribute is in mode default/on.
The change
event applies.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, autocomplete
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, maxlength
, min
, multiple
, pattern
, placeholder
, readonly
, size
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: files
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
, setSelectionRange()
, stepDown()
, and stepUp()
methods.
The input
event does not apply.
The input
element represents a control that, when used in conjunction with other input
elements, forms a radio button group in which only one control can have its checkedness state set to true. If the element's checkedness state is true, the control represents the selected control in the group, and if it is false, it indicates a control in the group that is not selected.
The radio button group that contains an input
element a also contains all the other input
elements b that fulfill all of the following conditions:
input
element b's type
attribute is in the Radio Button state.name
attribute, their name
attributes are not empty, and the value of a's name
attribute is a compatibility caseless match for the value of b's name
attribute.A document must not contain an input
element whose radio button group contains only that element.
If none of the radio buttons in a radio button group are checked when they are inserted into the document, then they will all be initially unchecked in the interface, until such time as one of them is checked (either by the user or by script).
The following common input
element content attributes and IDL attributes apply to the element: checked
and required
content attributes; checked
and value
IDL attributes.
The value
IDL attribute is in mode default/on.
The change
event applies.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, autocomplete
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, maxlength
, min
, multiple
, pattern
, placeholder
, readonly
, size
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: files
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
, setSelectionRange()
, stepDown()
, and stepUp()
methods.
The input
event does not apply.
The input
element represents a list of selected files, each file consisting of a file name, a file type, and a file body (the contents of the file).
The accept
attribute may be specified to provide user agents with a hint of what file types will be accepted.
If specified, the attribute must consist of a set of comma-separated tokens, each of which must be an ASCII case-insensitive match for one of the following:
audio/*
video/*
image/*
The tokens must not be ASCII case-insensitive matches for any of the other tokens (i.e. duplicates are not allowed).
User agents may use the value of this attribute to display a more appropriate user interface than a generic file picker. For instance, given the value image/*
, a user agent could offer the user the option of using a local camera or selecting a photograph from their photo collection; given the value audio/*
, a user agent could offer the user the option of recording a clip using a headset microphone.
For historical reasons, the value
IDL attribute prefixes the filename with the string "C:\fakepath\
". Some legacy user agents actually included the full path (which was a security vulnerability). As a result of this, obtaining the filename from the value
IDL attribute in a backwards-compatible way is non-trivial. The following function extracts the filename in a suitably compatible manner:
function extractFilename(path) { var x; x = path.lastIndexOf('\\'); if (x >= 0) // Windows-based path return path.substr(x+1); x = path.lastIndexOf('/'); if (x >= 0) // Unix-based path return path.substr(x+1); return path; // just the filename }
This can be used as follows:
<p><input type=file name=image onchange="updateFilename(this.value)"></p> <p>The name of the file you picked is: <span id="filename">(none)</span></p> <script> function updateFilename(path) { var name = extractFilename(path); document.getElementById('filename').textContent = name; } </script>
The following common input
element content attributes apply to the element:
The following common input
element content attributes and IDL attributes apply to the element: accept
, multiple
, and required
; files
and value
IDL attributes.
The value
IDL attribute is in mode filename.
The change
event applies.
The following content attributes must not be specified and do not apply to the element: alt
, autocomplete
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, maxlength
, min
, pattern
, placeholder
, readonly
, size
, src
, step
, and width
.
The element's value
attribute must be omitted.
The following IDL attributes and methods do not apply to the element: checked
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
, setSelectionRange()
, stepDown()
, and stepUp()
methods.
The input
event does not apply.
The input
element represents a button that, when activated, submits the form. The element is a button, specifically a submit button.
The formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
attributes are attributes for form submission.
The formnovalidate
attribute can be used to make submit buttons that do not trigger the constraint validation.
The following common input
element content attributes and IDL attributes apply to the element: formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
content attributes; value
IDL attribute.
The value
IDL attribute is in mode default.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, autocomplete
, checked
, dirname
, height
, list
, max
,
maxlength
, min
, multiple
, pattern
, placeholder
, readonly
, required
, size
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
,
setSelectionRange()
, stepDown()
, and stepUp()
methods.
The input
element represents either an image from which a user can select a coordinate and submit the form, or alternatively a button from which the user can submit the form. The element is a button, specifically a submit button.
The image is given by the src
attribute. The src
attribute must be present, and must contain a valid non-empty URL potentially surrounded by spaces referencing a non-interactive, optionally animated, image resource that is neither paged nor scripted.
The alt
attribute provides the textual label for the alternative button for users and user agents who cannot use the image. The alt
attribute must also be present, and must contain a non-empty string.
The input
element supports dimension attributes.
The formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
attributes are attributes for form submission.
The following common input
element content attributes and IDL attributes apply to the element: alt
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, src
, and width
content attributes; value
IDL attribute.
The value
IDL attribute is in mode default.
The following content attributes must not be specified and do not apply to the element: accept
, autocomplete
, checked
, dirname
, list
, max
, maxlength
, min
, multiple
, pattern
, placeholder
, readonly
, required
, size
, and step
.
The element's value
attribute must be omitted.
The following IDL attributes and methods do not apply to the element: checked
, files
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
,
setSelectionRange()
, stepDown()
, and stepUp()
methods.
Many aspects of this state's behavior are similar to the behavior of the img
element. Readers are encouraged to read that section, where many of the same requirements are described in more detail.
The input
element represents a button that, when activated, resets the form. The element is a button.
The value
IDL attribute applies to this element and is in mode default.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, autocomplete
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, maxlength
, min
, multiple
,
pattern
, placeholder
, readonly
, required
, size
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
,
setSelectionRange()
, stepDown()
, and stepUp()
methods.
The input
element represents a button with no default behavior. A label for the button must be provided in the value
attribute, though it may be the empty string. The element is a button.
The value
IDL attribute applies to this element and is in mode default.
The following content attributes must not be specified and do not apply to the element: accept
, alt
, autocomplete
, checked
, dirname
, formaction
, formenctype
, formmethod
, formnovalidate
, formtarget
, height
, list
, max
, maxlength
, min
, multiple
,
pattern
, placeholder
, readonly
, required
, size
, src
, step
, and width
.
The following IDL attributes and methods do not apply to the element: checked
, files
, list
, selectedOption
, selectionStart
, selectionEnd
, selectionDirection
, valueAsDate
, and valueAsNumber
IDL attributes; select()
,
setSelectionRange()
, stepDown()
, and stepUp()
methods.
input
element attributesautocomplete
attributeUser agents sometimes have features for helping users fill forms in, for example prefilling the user's address based on earlier user input.
The autocomplete
attribute is an enumerated attribute. The attribute has three states. The on
keyword maps to the on state, and the off
keyword maps to the off state. The attribute may also be omitted. The missing value default is the default state.
The off state indicates either that the control's input data is particularly sensitive (for example the activation code for a nuclear weapon); or that it is a value that will never be reused (for example a one-time-key for a bank login) and the user will therefore have to explicitly enter the data each time, instead of being able to rely on the UA to prefill the value for him; or that the document provides its own autocomplete mechanism and does not want the user agent to provide autocompletion values.
Conversely, the on state indicates that the value is not particularly sensitive and the user can expect to be able to rely on his user agent to remember values he has entered for that control.
The default state indicates that the user agent is to use the autocomplete
attribute on the element's form owner instead. (By default, the autocomplete
attribute of form
elements is in the on state.)
Banks frequently do not want UAs to prefill login information:
<p><label>Account: <input type="text" name="ac" autocomplete="off"></label></p> <p><label>PIN: <input type="password" name="pin" autocomplete="off"></label></p>
dirname
attributeThe dirname
attribute, when it applies, is a form control dirname
attribute.
In this example, a form contains a text field and a submission button:
<form action="addcomment.cgi" method=post> <p><label>Comment: <input type=text name="comment" dirname="comment.dir" required></label></p> <p><button name="mode" type=submit value="add">Post Comment</button></p> </form>
When the user submits the form, the user agent includes three fields, one called "comment", one called "comment.dir", and one called "mode"; so if the user types "Hello", the submission body might be something like:
comment=Hello&comment.dir=ltr&mode=add
If the user manually switches to a right-to-left writing direction and enters "مرحبًا", the submission body might be something like:
comment=%D9%85%D8%B1%D8%AD%D8%A8%D9%8B%D8%A7&comment.dir=rtl&mode=add
list
attributeThe list
attribute is used to identify an element that lists predefined options suggested to the user.
If present, its value must be the ID of a datalist
element in the same document.
This URL field offers some suggestions.
<label>Homepage: <input name=hp type=url list=hpurls></label> <datalist id=hpurls> <option value="http://www.google.com/" label="Google"> <option value="http://www.reddit.com/" label="Reddit"> </datalist>
Other URLs from the user's history might show also; this is up to the user agent.
This example demonstrates how to design a form that uses the autocompletion list feature while still degrading usefully in legacy user agents.
If the autocompletion list is merely an aid, and is not important to the content, then simply using a datalist
element with children option
elements is enough. To prevent the values from being rendered in legacy user agents, they should be placed inside the value
attribute instead of inline.
<p> <label> Enter a breed: <input type="text" name="breed" list="breeds"> <datalist id="breeds"> <option value="Abyssinian"> <option value="Alpaca"> <!-- ... --> </datalist> </label> </p>
However, if the values need to be shown in legacy UAs, then fallback content can be placed inside the datalist
element, as follows:
<p> <label> Enter a breed: <input type="text" name="breed" list="breeds"> </label> <datalist id="breeds"> <label> or select one from the list: <select name="breed"> <option value=""> (none selected) <option>Abyssinian <option>Alpaca <!-- ... --> </select> </label> </datalist> </p>
The fallback content will only be shown in UAs that don't support datalist
. The options, on the other hand, will be detected by all UAs, even though they are not direct children of the datalist
element.
Note that if an option
element used in a datalist
is selected
, it will be selected by default by legacy UAs (because it affects the select
), but it will not have any effect on the input
element in UAs that support datalist
.
readonly
attributeThe readonly
attribute is a boolean attribute that controls whether or not the user can edit the form control.
In the following example, the existing product identifiers cannot be modified, but they are still displayed as part of the form, for consistency with the row representing a new product (where the identifier is not yet filled in).
<form action="products.cgi" method=post enctype="multipart/form-data"> <table> <tr> <th> Product ID <th> Product name <th> Price <th> Action <tr> <td> <input readonly name="1.pid" value="H412"> <td> <input required name="1.pname" value="Floor lamp Ulke"> <td> $<input required type=number min=0 step=0.01 name="1.pprice" value="49.99"> <td> <button formnovalidate name="action" value="delete:1">Delete</button> <tr> <td> <input readonly name="2.pid" value="FG28"> <td> <input required name="2.pname" value="Table lamp Ulke"> <td> $<input required type=number min=0 step=0.01 name="2.pprice" value="24.99"> <td> <button formnovalidate name="action" value="delete:2">Delete</button> <tr> <td> <input required name="3.pid" value="" pattern="[A-Z0-9]+"> <td> <input required name="3.pname" value=""> <td> $<input required type=number min=0 step=0.01 name="3.pprice" value=""> <td> <button formnovalidate name="action" value="delete:3">Delete</button> </table> <p> <button formnovalidate name="action" value="add">Add</button> </p> <p> <button name="action" value="update">Save</button> </p> </form>
size
attributeThe size
attribute gives the number of characters that, in a visual rendering, the user agent is to allow the user to see while editing the element's value.
The size
attribute, if specified, must have a value that is a valid non-negative integer greater than zero.
required
attributeThe required
attribute is a boolean attribute. When specified, the element is required.
The following form has two required fields, one for an e-mail address and one for a password. It also has a third field that is only considerd valid if the user types the same password in the password field and this third field.
<h1>Create new account</h1> <form action="/newaccount" method=post oninput="up2.setCustomValidity(up2.value != up.value ? 'Passwords do not match.' : '')"> <p> <label for="username">E-mail address:</label> <input id="username" type=email required name=un> <p> <label for="password1">Password:</label> <input id="password1" type=password required name=up> <p> <label for="password2">Confirm password:</label> <input id="password2" type=password name=up2> <p> <input type=submit value="Create account"> </form>
multiple
attributeThe multiple
attribute is a boolean attribute that indicates whether the user is to be allowed to specify more than one value.
The following extract shows how an e-mail client's "Cc" field could accept multiple e-mail addresses.
<label>Cc: <input type=email multiple name=cc></label>
If the user had, amongst many friends in his user contacts database, two friends "Arthur Dent" (with address "art@example.net") and "Adam Josh" (with address "adamjosh@example.net"), then, after the user has typed "a", the user agent might suggest these two e-mail addresses to the user.
The page could also link in the user's contacts database from the site:
<label>Cc: <input type=email multiple name=cc list=contacts></label> ... <datalist id="contacts"> <option value="hedral@damowmow.com"> <option value="pillar@example.com"> <option value="astrophy@cute.example"> <option value="astronomy@science.example.org"> </datalist>
Suppose the user had entered "bob@example.net" into this text field, and then started typing a second e-mail address starting with "a". The user agent might show both the two friends mentioned earlier, as well as the "astrophy" and "astronomy" values given in the datalist
element.
The following extract shows how an e-mail client's "Attachments" field could accept multiple files for upload.
<label>Attachments: <input type=file multiple name=att></label>
maxlength
attributeThe maxlength
attribute is a form control maxlength
attribute.
If the input
element has a maximum allowed value length, then the code-point length of the value of the element's value
attribute must be equal to or less than the element's maximum allowed value length.
The following extract shows how a messaging client's text entry could be arbitrarily restricted to a fixed number of characters, thus forcing any conversation through this medium to be terse and discouraging intelligent discourse.
What are you doing? <input name=status maxlength=140>
pattern
attributeThe pattern
attribute specifies a regular expression against which the control's value, or, when the multiple
attribute applies and is set, the control's values, are to be checked.
If specified, the attribute's value must match the JavaScript Pattern production. [ECMA262]
When an input
element has a pattern
attribute specified, authors should include a title
attribute to give a description of the pattern. User agents may use the contents of this attribute, if it is present, when informing the user that the pattern is not matched, or at any other suitable time, such as in a tooltip or read out by assistive technology when the control gains focus.
For example, the following snippet:
<label> Part number: <input pattern="[0-9][A-Z]{3}" name="part" title="A part number is a digit followed by three uppercase letters."/> </label>
...could cause the UA to display an alert such as:
A part number is a digit followed by three uppercase letters. You cannot submit this form when the field is incorrect.
When a control has a pattern
attribute, the title
attribute, if used, must describe the pattern. Additional information could also be included, so long as it assists the user in filling in the control. Otherwise, assistive technology would be impaired.
For instance, if the title attribute contained the caption of the control, assistive technology could end up saying something like The text you have entered does not match the required pattern. Birthday, which is not useful.
UAs may still show the title
in non-error situations (for example, as a tooltip when hovering over the control), so authors should be careful not to word title
s as if an error has necessarily occurred.
min
and max
attributesThe min
and max
attributes indicate the allowed range of values for the element.
The max
attribute's value (the maximum) must not be less than the min
attribute's value (its minimum).
An element has range limitations if it has a defined minimum or a defined maximum.
The following date control limits input to dates that are before the 1980s:
<input name=bday type=date max="1979-12-31">
The following number control limits input to whole numbers greater than zero:
<input name=quantity required type=number min=1 value=1>
step
attributeThe step
attribute indicates the granularity that is expected (and required) of the value, by limiting the allowed values.
The step
attribute, if specified, must either have a value that is a valid floating point number that parses to a number that is greater than zero, or must have a value that is an ASCII case-insensitive match for the string "any
".
The following range control only accepts values in the range 0..1, and allows 256 steps in that range:
<input name=opacity type=range min=0 max=1 step=0.00392156863>
The following control allows any time in the day to be selected, with any accuracy (e.g. thousandth-of-a-second accuracy or more):
<input name=favtime type=time step=any>
Normally, time controls are limited to an accuracy of one minute.
placeholder
attributeThe placeholder
attribute represents a short hint (a word or short phrase) intended to aid the user with data entry. A hint could be a sample value or a brief description of the expected format. The attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters.
For a longer hint or other advisory text, the title
attribute is more appropriate.
The placeholder
attribute should not be used as an alternative to a label
.
Here is an example of a mail configuration user interface that uses the placeholder
attribute:
<fieldset> <legend>Mail Account</legend> <p><label>Name: <input type="text" name="fullname" placeholder="John Ratzenberger"></label></p> <p><label>Address: <input type="email" name="address" placeholder="john@example.net"></label></p> <p><label>Password: <input type="password" name="password"></label></p> <p><label>Description: <input type="text" name="desc" placeholder="My Email Account"></label></p> </fieldset>
input
element APIsvalue
[ = value ]Returns the current value of the form control.
Can be set, to change the value.
Throws an INVALID_STATE_ERR
exception if it is set to any value other than the empty string when the control is a file upload control.
checked
[ = value ]Returns the current checkedness of the form control.
Can be set, to change the checkedness.
files
Returns a FileList
object listing the selected files of the form control.
Returns null if the control isn't a file control.
valueAsDate
[ = value ]Returns a Date
object representing the form control's value, if applicable; otherwise, returns null.
Can be set, to change the value.
Throws an INVALID_STATE_ERR
exception if the control isn't date- or time-based.
valueAsNumber
[ = value ]Returns a number representing the form control's value, if applicable; otherwise, returns null.
Can be set, to change the value.
Throws an INVALID_STATE_ERR
exception if the control is neither date- or time-based nor numeric.
stepUp
( [ n ] )stepDown
( [ n ] )Changes the form control's value by the value given in the step
attribute, multiplied by n. The default value for n is 1.
Throws INVALID_STATE_ERR
exception if the control is neither date- or time-based nor numeric, if the step
attribute's value is "any
", if the current value could not be parsed, or if stepping in the given direction by the given amount would take the value out of range.
list
Returns the datalist
element indicated by the list
attribute.
selectedOption
Returns the option
element from the datalist
element indicated by the list
attribute that matches the form control's value.
button
elementautofocus
disabled
form
formaction
formenctype
formmethod
formnovalidate
formtarget
name
type
value
interface HTMLButtonElement : HTMLElement { attribute boolean autofocus; attribute boolean disabled; readonly attribute HTMLFormElement form; attribute DOMString formAction; attribute DOMString formEnctype; attribute DOMString formMethod; attribute DOMString formNoValidate; attribute DOMString formTarget; attribute DOMString name; attribute DOMString type; attribute DOMString value; readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); readonly attribute NodeList labels; };
The button
element represents a button.
The element is a button.
The type
attribute controls the behavior of the button when it is activated. It is an enumerated attribute. The following table lists the keywords and states for the attribute — the keywords in the left column map to the states in the cell in the second column on the same row as the keyword.
Keyword | State | Brief description |
---|---|---|
submit |
Submit Button | Submits the form. |
reset |
Reset Button | Resets the form. |
button |
Button | Does nothing. |
The missing value default is the Submit Button state.
If the type
attribute is in the Submit Button state, the element is specifically a submit button.
The form
attribute is used to explicitly associate the button
element with its form owner. The name
attribute represents the element's name. The disabled
attribute is used to make the control non-interactive and to prevent its value from being submitted. The autofocus
attribute controls focus. The formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
attributes are attributes for form submission.
The formnovalidate
attribute can be used to make submit buttons that do not trigger the constraint validation.
The formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
must not be specified if the element's type
attribute is not in the Submit Button state.
The value
attribute gives the element's value for the purposes of form submission. The element's value is the value of the element's value
attribute, if there is one, or the empty string otherwise.
A button (and its value) is only included in the form submission if the button itself was used to initiate the form submission.
The value
IDL attribute must reflect the content attribute of the same name.
The type
IDL attribute must reflect the content attribute of the same name, limited to only known values.
The following button is labeled "Show hint" and pops up a dialog box when activated:
<button type=button onclick="alert('This 15-20 minute piece was composed by George Gershwin.')"> Show hint </button>
select
elementoption
or optgroup
elements.autofocus
disabled
form
multiple
name
required
size
interface HTMLSelectElement : HTMLElement { attribute boolean autofocus; attribute boolean disabled; readonly attribute HTMLFormElement form; attribute boolean multiple; attribute DOMString name; attribute boolean required; attribute unsigned long size; readonly attribute DOMString type; readonly attribute HTMLOptionsCollection options; attribute unsigned long length; getter any item(in unsigned long index); any namedItem(in DOMString name); void add(in HTMLElement element, in optional HTMLElement before); void add(in HTMLElement element, in long before); void remove(in long index); readonly attribute HTMLCollection selectedOptions; attribute long selectedIndex; attribute DOMString value; readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); readonly attribute NodeList labels; };
The select
element represents a control for selecting amongst a set of options.
The multiple
attribute is a boolean attribute. If the attribute is present, then the select
element represents a control for selecting zero or more options from the list of options. If the attribute is absent, then the select
element represents a
control for selecting a single option from the list of options.
The size
attribute gives the number of options to show to the user. The size
attribute, if specified, must have a value that is a valid non-negative integer greater than zero. If the multiple
attribute is present, then the size
attribute's default value is 4. If the multiple
attribute is absent, then the size
attribute's default value is 1.
The list of options for a select
element consists of all the option
element children of the select
element, and all the option
element children of all the optgroup
element children of the select
element, in tree order.
The required
attribute is a boolean attribute. When specified, the user will be required to select a value before submitting the form.
If a select
element has a required
attribute specified, does not have a multiple
attribute specified, and has a display size of 1; and if the value of the first option
element in the select
element's list of options
(if any) is the empty string, and that option
element's parent node is the select
element (and not an optgroup
element), then that option
is the select
element's placeholder label option.
If a select
element has a required
attribute specified, does not have a multiple
attribute specified, and has a display size of 1, then the select
element must have a placeholder label option.
The form
attribute is used to explicitly associate the select
element with its form owner. The name
attribute represents the element's name. The disabled
attribute is used to make the control non-interactive and to prevent its value from being submitted. The autofocus
attribute controls focus.
type
Returns "select-multiple
" if the element has a multiple
attribute, and "select-one
" otherwise.
options
Returns an HTMLOptionsCollection
of the list of options.
length
[ = value ]Returns the number of elements in the list of options.
When set to a smaller number, truncates the number of option
elements in the select
.
When set to a greater number, adds new blank option
elements to the select
.
item
(index)Returns the item with index index from the list of options. The items are sorted in tree order.
Returns null if index is out of range.
namedItem
(name)Returns the item with ID or name
name from the list of options.
If there are multiple matching items, then a NodeList
object containing all those elements is returned.
Returns null if no element with that ID could be found.
add
(element [, before ])Inserts element before the node given by before.
The before argument can be a number, in which case element is inserted before the item with that number, or an element from the list of options, in which case element is inserted before that element.
If before is omitted, null, or a number out of range, then element will be added at the end of the list.
This method will throw a HIERARCHY_REQUEST_ERR
exception if element is an ancestor of the element into which it is to be inserted. If element is not an option
or optgroup
element, then the method does nothing.
selectedOptions
Returns an HTMLCollection
of the list of options that are selected.
selectedIndex
[ = value ]Returns the index of the first selected item, if any, or −1 if there is no selected item.
Can be set, to change the selection.
value
[ = value ]Returns the value of the first selected item, if any, or the empty string if there is no selected item.
Can be set, to change the selection.
The multiple
, required
, and size
IDL attributes must reflect the respective content attributes of the same name. The size
IDL attribute is limited to only non-negative numbers, with the default value zero (which for historical reasons is different from the default value of the size
content attribute that it reflects).
The following example shows how a select
element can be used to offer the user with a set of options from which the user can select a single option. The default option is preselected.
<p> <label for="unittype">Select unit type:</label> <select id="unittype" name="unittype"> <option value="1"> Miner </option> <option value="2"> Puffer </option> <option value="3" selected> Snipey </option> <option value="4"> Max </option> <option value="5"> Firebot </option> </select> </p>
Here, the user is offered a set of options from which he can select any number. By default, all five options are selected.
<p> <label for="allowedunits">Select unit types to enable on this map:</label> <select id="allowedunits" name="allowedunits" multiple> <option value="1" selected> Miner </option> <option value="2" selected> Puffer </option> <option value="3" selected> Snipey </option> <option value="4" selected> Max </option> <option value="5" selected> Firebot </option> </select> </p>
datalist
elementoption
elements.interface HTMLDataListElement : HTMLElement { readonly attribute HTMLCollection options; };
The datalist
element represents a set of option
elements that represent predefined options for other controls. The contents of the element represents fallback content for legacy user agents, intermixed with option
elements that represent the predefined options. In the rendering, the datalist
element represents nothing.
The datalist
element is hooked up to an input
element using the list
attribute on the input
element.
Each option
element that is a descendant of the datalist
element, that is not disabled, and whose value is a string that isn't the empty string, represents a suggestion. Each suggestion has a value and a label.
options
Returns an HTMLCollection
of the options
elements of the table.
optgroup
elementselect
element.option
elements.disabled
label
interface HTMLOptGroupElement : HTMLElement { attribute boolean disabled; attribute DOMString label; };
The optgroup
element represents a group of option
elements with a common label.
The element's group of option
elements consists of the option
elements that are children of the optgroup
element.
The disabled
attribute is a boolean attribute and can be used to disable a group of option
elements together.
The label
attribute must be specified. Its value gives the name of the group, for the purposes of the user interface.
The disabled
and label
attributes must reflect the respective content attributes of the same name.
The following snippet shows how a set of lessons from three courses could be offered in a select
drop-down widget:
<form action="courseselector.dll" method="get"> <p>Which course would you like to watch today? <p><label>Course: <select name="c"> <optgroup label="8.01 Physics I: Classical Mechanics"> <option value="8.01.1">Lecture 01: Powers of Ten <option value="8.01.2">Lecture 02: 1D Kinematics <option value="8.01.3">Lecture 03: Vectors <optgroup label="8.02 Electricity and Magnestism"> <option value="8.02.1">Lecture 01: What holds our world together? <option value="8.02.2">Lecture 02: Electric Field <option value="8.02.3">Lecture 03: Electric Flux <optgroup label="8.03 Physics III: Vibrations and Waves"> <option value="8.03.1">Lecture 01: Periodic Phenomenon <option value="8.03.2">Lecture 02: Beats <option value="8.03.3">Lecture 03: Forced Oscillations with Damping </select> </label> <p><input type=submit value="▶ Play"> </form>
option
elementselect
element.datalist
element.optgroup
element.disabled
label
selected
value
[NamedConstructor=Option(), NamedConstructor=Option(in DOMString text), NamedConstructor=Option(in DOMString text, in DOMString value), NamedConstructor=Option(in DOMString text, in DOMString value, in boolean defaultSelected), NamedConstructor=Option(in DOMString text, in DOMString value, in boolean defaultSelected, in boolean selected)] interface HTMLOptionElement : HTMLElement { attribute boolean disabled; readonly attribute HTMLFormElement form; attribute DOMString label; attribute boolean defaultSelected; attribute boolean selected; attribute DOMString value; attribute DOMString text; readonly attribute long index; };
The option
element represents an option in a select
element or as part of a list of suggestions in a datalist
element.
In certain circumstances described in the definition of the select
element, an option
element can be a select
element's placeholder label option. A placeholder label option does not represent an actual option, but instead represents a label for the select
control.
The disabled
attribute is a boolean attribute. An option
element is disabled if its disabled
attribute is present or if it is a child of an optgroup
element whose disabled
attribute is present.
The label
attribute provides a label for element. The label of an option
element is the value of the label
attribute, if there is one, or the textContent
of the element, if there isn't.
The value
attribute provides a value for element. The value of an option
element is the value of the value
attribute, if there is one, or the textContent
of the element, if there isn't.
The selected
attribute is a boolean attribute. It represents the default selectedness of the element.
A select
element whose multiple
attribute is not specified must not have more than one descendant option
element with its selected
attribute set.
selected
Returns true if the element is selected, and false otherwise.
Can be set, to override the current state of the element.
index
Returns the index of the element in its select
element's options
list.
form
Returns the element's form
element, if any, or null otherwise.
text
Same as textContent
, except that spaces are collapsed.
Option
( [ text [, value [, defaultSelected [, selected ] ] ] ] )Returns a new option
element.
The text argument sets the contents of the element.
The value argument sets the value
attribute.
The defaultSelected argument sets the selected
attribute.
The selected argument sets whether or not the element is selected. If it is omitted, even if the defaultSelected argument is true, the element is not selected.
The disabled
and label
IDL attributes must reflect the respective content attributes of the same name. The defaultSelected
IDL attribute must reflect the selected
content attribute.
textarea
elementautofocus
cols
dirname
disabled
form
maxlength
name
placeholder
readonly
required
rows
wrap
interface HTMLTextAreaElement : HTMLElement { attribute boolean autofocus; attribute unsigned long cols; attribute DOMString dirName; attribute boolean disabled; readonly attribute HTMLFormElement form; attribute long maxLength; attribute DOMString name; attribute DOMString placeholder; attribute boolean readOnly; attribute boolean required; attribute unsigned long rows; attribute DOMString wrap; readonly attribute DOMString type; attribute DOMString defaultValue; attribute DOMString value; readonly attribute unsigned long textLength; readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); readonly attribute NodeList labels; void select(); attribute unsigned long selectionStart; attribute unsigned long selectionEnd; attribute DOMString selectionDirection; void setSelectionRange(in unsigned long start, in unsigned long end, in optional DOMString direction); };
The textarea
element represents a multiline plain text edit control. The contents of the control represent the control's default value.
The readonly
attribute is a boolean attribute used to control whether the text can be edited by the user or not.
The cols
attribute specifies the expected maximum number of characters per line. If the cols
attribute is specified, its value must be a valid non-negative integer greater than zero.
The rows
attribute specifies the number of lines to show. If the rows
attribute is specified, its value must be a valid non-negative integer greater than zero.
The wrap
attribute is an enumerated attribute with two keywords and states: the soft
keyword which maps to the Soft state, and the hard
keyword which maps to the Hard state. The missing value default is the Soft state.
The Soft state indicates that the text in the textarea
is not to be wrapped when it is submitted (though it can still be wrapped in the rendering).
The Hard state indicates that the text in the textarea
is to have newlines added by the user agent so that the text is wrapped when it is submitted.
If the element's wrap
attribute is in the Hard state, the cols
attribute must be specified.
The maxlength
attribute is a form control maxlength
attribute controlled by the textarea
element's dirty value flag.
If the textarea
element has a maximum allowed value length, then the element's children must be such that the code-point length of the value of the element's textContent
IDL attribute is equal to or less than the element's maximum allowed value length.
The required
attribute is a boolean attribute. When specified, the user will be required to enter a value before submitting the form.
The placeholder
attribute represents a hint (a word or short phrase) intended to aid the user with data entry. A hint could be a sample value or a brief description of the expected format. The attribute, if specified, must have a value that contains no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR) characters.
For a longer hint or other advisory text, the title
attribute is more appropriate.
The placeholder
attribute should not be used as an alternative to a label
.
The dirname
attribute is a form control dirname
attribute.
The form
attribute is used to explicitly associate the textarea
element with its form owner. The name
attribute represents the element's name. The disabled
attribute is used to make the control non-interactive and to prevent its value from being submitted. The autofocus
attribute controls focus.
type
Returns the string "textarea
".
value
Returns the current value of the element.
Can be set, to change the value.
The cols
, placeholder
, required
, rows
, and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.
Here is an example of a textarea
being used for unrestricted free-form text input in a form:
<p>If you have any comments, please let us know: <textarea cols=80 name=comments></textarea></p>
To specify a maximum length for the comments, one can use the maxlength
attribute:
<p>If you have any short comments, please let us know: <textarea cols=80 name=comments maxlength=200></textarea></p>
To give a default value, text can be included inside the element:
<p>If you have any comments, please let us know: <textarea cols=80 name=comments>You rock!</textarea></p>
To have the browser submit the directionality of the element along with the value, the dirname
attribute can be specified:
<p>If you have any comments, please let us know (you may use either English or Hebrew for your comments): <textarea cols=80 name=comments dirname=comments.dir></textarea></p>
keygen
elementautofocus
challenge
disabled
form
keytype
name
interface HTMLKeygenElement : HTMLElement { attribute boolean autofocus; attribute DOMString challenge; attribute boolean disabled; readonly attribute HTMLFormElement form; attribute DOMString keytype; attribute DOMString name; readonly attribute DOMString type; readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); readonly attribute NodeList labels; };
The keygen
element represents a key pair generator control. When the control's form is submitted, the private key is stored in the local keystore, and the public key is packaged and sent to the server.
The challenge
attribute may be specified. Its value will be packaged with the submitted key.
The keytype
attribute is an enumerated attribute. The following table lists the keywords and states for the attribute — the keywords in the left column map to the states listed in the cell in the second column on the same row as the keyword. User agents are not required to support these values, and must only recognize values whose corresponding algorithms they support.
Keyword | State |
---|---|
rsa |
RSA |
The invalid value default state is the unknown state. The missing value default state is the RSA state, if it is supported, or the unknown state otherwise.
This specification does not specify what key types user agents are to support — it is possible for a user agent to not support any key types at all.
The form
attribute is used to explicitly associate the keygen
element with its form owner. The name
attribute represents the element's name. The disabled
attribute is used to make the control non-interactive and to prevent its value from being submitted. The autofocus
attribute controls focus.
type
Returns the string "keygen
".
The challenge
IDL attribute must reflect the content attribute of the same name.
The keytype
IDL attribute must reflect the content attribute of the same name, limited to only known values.
This specification does not specify how the private key generated is to be used. It is expected that after receiving the SignedPublicKeyAndChallenge
(SPKAC) structure, the server will generate a client certificate and offer it back to the user for download; this certificate, once downloaded and stored in the key store along with the private key, can then be used to authenticate to services that use TLS and certificate authentication.
To generate a key pair, add the private key to the user's key store, and submit the public key to the server, markup such as the following can be used:
<form action="processkey.cgi" method="post" enctype="multipart/form-data"> <p><keygen name="key"></p> <p><input type=submit value="Submit key..."></p> </form>
The server will then receive a form submission with a packaged RSA public key as the value of "key
". This can then be used for various purposes, such as generating a client certificate, as mentioned above.
output
elementfor
form
name
interface HTMLOutputElement : HTMLElement { [PutForwards=value] readonly attribute DOMSettableTokenList htmlFor; readonly attribute HTMLFormElement form; attribute DOMString name; readonly attribute DOMString type; attribute DOMString defaultValue; attribute DOMString value; readonly attribute boolean willValidate; readonly attribute ValidityState validity; readonly attribute DOMString validationMessage; boolean checkValidity(); void setCustomValidity(in DOMString error); readonly attribute NodeList labels; };
The output
element represents the result of a calculation.
The for
content attribute allows an explicit relationship to be made between the result of a calculation and the elements that represent the values that went into the calculation or that otherwise influenced the calculation. The for
attribute, if specified, must contain a string consisting of an unordered set of unique space-separated tokens that are case-sensitive, each of which must have the value of an ID of an element in the same Document
.
The form
attribute is used to explicitly associate the output
element with its form owner. The name
attribute represents the element's name.
value
[ = value ]Returns the element's current value.
Can be set, to change the value.
defaultValue
[ = value ]Returns the element's current default value.
Can be set, to change the default value.
type
Returns the string "output
".
The htmlFor
IDL attribute must reflect the for
content attribute.
A simple calculator could use output
for its display of calculated results:
<form onsubmit="return false" oninput="o.value = a.valueAsNumber + b.valueAsNumber"> <input name=a type=number step=any> + <input name=b type=number step=any> = <output name=o></output> </form>
progress
elementprogress
element descendants.value
max
form
interface HTMLProgressElement : HTMLElement { attribute double value; attribute double max; readonly attribute double position; readonly attribute HTMLFormElement form; readonly attribute NodeList labels; };
The progress
element represents the completion progress of a task. The progress is either indeterminate, indicating that progress is being made but that it is not clear how much more work remains to be done before the task is complete (e.g. because the task is waiting for a remote host to respond), or the progress is a number in the range zero to a maximum, giving the fraction of work that has so far been completed.
There are two attributes that determine the current task completion represented by the element. The value
attribute specifies how much of the task has been completed, and the max
attribute specifies how much work the task requires in total. The units are arbitrary and not specified.
To make an determinate progress bar, add a value
attribute with the current progress (either a number from 0.0 to 1.0, or, if the max
attribute is specified, a number from 0 to the value of the max
attribute. To make an indeterminate progress bar, remove the value
attribute.
Authors are encouraged to also include the current value and the maximum value inline as text inside the element, so that the progress is made available to users of legacy user agents.
Here is a snippet of a Web application that shows the progress of some automated task:
<section> <h2>Task Progress</h2> <p>Progress: <progress id="p" max=100><span>0</span>%</progress></p> <script> var progressBar = document.getElementById('p'); function updateProgress(newValue) { progressBar.value = newValue; progressBar.getElementsByTagName('span')[0].textContent = newValue; } </script> </section>
(The updateProgress()
method in this example would be called by some other code on the page to update the actual progress bar as the task progressed.)
The value
and max
attributes, when present, must have values that are valid floating point numbers. The value
attribute, if present, must have a value equal to or greater than zero, and less than or equal to the value of the max
attribute, if present, or 1.0, otherwise. The max
attribute, if present, must have a value greater than zero.
The progress
element is the wrong element to use for something that is just a gauge, as opposed to task progress. For instance, indicating disk space usage using progress
would be inappropriate. Instead, the meter
element is available for such use cases.
position
For a determinate progress bar (one with known current and maximum values), returns the result of dividing the current value by the maximum value.
For an indeterminate progress bar, returns −1.
If the progress bar is an indeterminate progress bar, then the value
IDL attribute, on getting, must return 0. Otherwise, it must return the current value. On setting, the given value must be converted to the best representation of the number as a floating point number and then the value
content attribute must be set to
that string.
The max
IDL attribute must reflect the content attribute of the same name. The default value for max
is 1.0.
meter
elementmeter
element descendants.value
min
max
low
high
optimum
form
interface HTMLMeterElement : HTMLElement { attribute double value; attribute double min; attribute double max; attribute double low; attribute double high; attribute double optimum; readonly attribute HTMLFormElement form; readonly attribute NodeList labels; };
The meter
element represents a scalar measurement within a known range, or a fractional value; for example disk usage, the relevance of a query result, or the fraction of a voting population to have selected a particular candidate.
This is also known as a gauge.
The meter
element should not be used to indicate progress (as in a progress bar). For that role, HTML provides a separate progress
element.
The meter
element also does not represent a scalar value of arbitrary range — for example, it would be wrong to use this to report a weight, or height, unless there is a known maximum value.
There are six attributes that determine the semantics of the gauge represented by the element.
The min
attribute specifies the lower bound of the range, and the max
attribute specifies the upper bound. The value
attribute specifies the value to have the gauge indicate as the "measured" value.
The other three attributes can be used to segment the gauge's range into "low", "medium", and "high" parts, and to indicate which part of the gauge is the "optimum" part. The low
attribute specifies the range that is considered to be the "low" part, and the high
attribute specifies the range that is considered to be the "high" part. The optimum
attribute gives the position that is "optimum"; if that is higher than the "high" value then this indicates that the higher the value, the better; if it's lower than the "low" mark then it indicates that lower values are better, and naturally if it is in between then it indicates that neither high nor low values are good.
The value
attribute must be specified. The value
, min
, low
, high
, max
, and optimum
attributes, when present, must have values that are valid floating point numbers.
In addition, the attributes' values are further constrained:
Let value be the value
attribute's number.
If the min
attribute attribute is specified, then let minimum be that attribute's value; otherwise, let it be zero.
If the max
attribute attribute is specified, then let maximum be that attribute's value; otherwise, let it be 1.0.
The following inequalities must hold, as applicable:
low
≤ maximum (if low
is specified)high
≤ maximum (if high
is specified)optimum
≤ maximum (if optimum
is specified)low
≤ high
(if both low
and high
are specified)If no minimum or maximum is specified, then the range is assumed to be 0..1, and the value thus has to be within that range.
Authors are encouraged to include a textual representation of the gauge's state in the element's contents, for users of user agents that do not support the meter
element.
The following examples show three gauges that would all be three-quarters full:
Storage space usage: <meter value=6 max=8>6 blocks used (out of 8 total)</meter> Voter turnout: <meter value=0.75><img alt="75%" src="graph75.png"></meter> Tickets sold: <meter min="0" max="100" value="75"></meter>
The following example is incorrect use of the element, because it doesn't give a range (and since the default maximum is 1, both of the gauges would end up looking maxed out):
<p>The grapefruit pie had a radius of <meter value=12>12cm</meter> and a height of <meter value=2>2cm</meter>.</p> <!-- BAD! -->
Instead, one would either not include the meter element, or use the meter element with a defined range to give the dimensions in context compared to other pies:
<p>The grapefruit pie had a radius of 12cm and a height of 2cm.</p> <dl> <dt>Radius: <dd> <meter min=0 max=20 value=12>12cm</meter> <dt>Height: <dd> <meter min=0 max=10 value=2>2cm</meter> </dl>
There is no explicit way to specify units in the meter
element, but the units may be specified in the title
attribute in free-form text.
The example above could be extended to mention the units:
<dl> <dt>Radius: <dd> <meter min=0 max=20 value=12 title="centimeters">12cm</meter> <dt>Height: <dd> <meter min=0 max=10 value=2 title="centimeters">2cm</meter> </dl>
The following markup:
<h3>Suggested groups</h3> <menu type="toolbar"> <a href="?cmd=hsg" onclick="hideSuggestedGroups()">Hide suggested groups</a> </menu> <ul> <li> <p><a href="/group/comp.infosystems.www.authoring.stylesheets/view">comp.infosystems.www.authoring.stylesheets</a> - <a href="/group/comp.infosystems.www.authoring.stylesheets/subscribe">join</a></p> <p>Group description: <strong>Layout/presentation on the WWW.</strong></p> <p><meter value="0.5">Moderate activity,</meter> Usenet, 618 subscribers</p> </li> <li> <p><a href="/group/netscape.public.mozilla.xpinstall/view">netscape.public.mozilla.xpinstall</a> - <a href="/group/netscape.public.mozilla.xpinstall/subscribe">join</a></p> <p>Group description: <strong>Mozilla XPInstall discussion.</strong></p> <p><meter value="0.25">Low activity,</meter> Usenet, 22 subscribers</p> </li> <li> <p><a href="/group/mozilla.dev.general/view">mozilla.dev.general</a> - <a href="/group/mozilla.dev.general/subscribe">join</a></p> <p><meter value="0.25">Low activity,</meter> Usenet, 66 subscribers</p> </li> </ul>
Might be rendered as follows:
User agents combine the value of the title
attribute and the other attributes to provide context-sensitive help or inline text detailing the actual values.
For example, the following snippet:
<meter min=0 max=60 value=23.2 title=seconds></meter>
...might cause the user agent to display a gauge with a tooltip saying "Value: 23.2 out of 60." on one line and "seconds" on a second line.
The form
attribute is used to explicitly associate the meter
element with its form owner.
The value
IDL attribute, on getting, must return the actual value. On setting, the given value must be converted to the best representation of the number as a floating point number and then the value
content attribute must be set to that string.
The min
, max
, low
, high
, and optimum
IDL attributes must reflect the respective content attributes of the same name.
The following example shows how a gauge could fall back to localized or pretty-printed text.
<p>Disk usage: <meter min=0 value=170261928 max=233257824>170 261 928 bytes used out of 233 257 824 bytes available</meter></p>
A form-associated element can have a relationship with a form
element, which is called the element's form owner. If a form-associated element is not associated with a form
element, its form owner is said to be null.
A form-associated element is, by default, associated with its ancestor form
element, but may have a form
attribute specified to override this.
This feature allows authors to work around the lack of support for nested form
elements.
If a form-associated element has a form
attribute specified, then that attribute's value must be the ID of a form
element in the element's owner Document
.
form
Returns the element's form owner.
Returns null if there isn't one.
The name
content attribute gives the name of the form control, as used in form submission and in the form
element's elements
object. If the attribute is specified, its value must not be the empty string.
Any non-empty value for name
is allowed, but the names "_charset_
" and "isindex
" are special:
isindex
This value, if used as the name of a Text control that is the first control in a form that is submitted using the application/x-www-form-urlencoded
mechanism, causes the submission to only include the value of this control, with no name.
_charset_
This value, if used as the name of a value
attribute, is automatically given a value during submission consisting of the submission character encoding.
The name
IDL attribute must reflect the name
content attribute.
The disabled
content attribute is a boolean attribute.
A form control is disabled if its disabled
attribute is set, or if it is a descendant of a fieldset
element whose disabled
attribute is set and is not a descendant of that fieldset
element's first legend
element child, if any.
The disabled
IDL attribute must reflect the disabled
content attribute.
The autofocus
content attribute allows the author to indicate that a control is to be focused as soon as the page is loaded, allowing the user to just start typing without having to manually focus the main control.
The autofocus
attribute is a boolean attribute.
There must not be more than one element in the document with the autofocus
attribute specified.
The autofocus
IDL attribute must reflect the content attribute of the same name.
In the following snippet, the text control would be focused when the document was loaded.
<input maxlength="256" name="q" value="" autofocus> <input type="submit" value="Search">
A form control maxlength
attribute, controlled by a dirty value flag, declares a limit on the number of characters a user can input.
If an element has its form control maxlength
attribute specified, the attribute's value must be a valid non-negative integer. If the attribute is specified and applying the rules for parsing non-negative integers to its value results in a number, then that number is the element's maximum allowed value length. If the attribute is omitted or parsing its value results in an error, then there is no maximum allowed value length.
Attributes for form submission can be specified both on form
elements and on submit buttons (elements that represent buttons that submit forms, e.g. an input
element whose type
attribute is in the Submit Button state).
The attributes for form submission that may be specified on form
elements are action
, enctype
, method
, novalidate
, and target
.
The corresponding attributes for form submission that may be specified on submit buttons are formaction
, formenctype
, formmethod
, formnovalidate
, and formtarget
. When omitted, they default to the values given on the corresponding attributes on the form
element.
The action
and formaction
content attributes, if specified, must have a value that is a valid non-empty URL potentially surrounded by spaces.
The action of an element is the value of the element's formaction
attribute, if the element is a submit button and has such an attribute, or the value of its form owner's action
attribute, if it has one, or else the empty string.
The method
and formmethod
content attributes are enumerated attributes with the following keywords and states:
get
, mapping to the state GET, indicating the HTTP GET method.post
, mapping to the state POST, indicating the HTTP POST method.The missing value default for these attributes is the GET state.
The method of an element is one of those states. If the element is a submit button and has a formmethod
attribute, then the element's method is that attribute's state; otherwise, it is the form owner's method
attribute's state.
The enctype
and formenctype
content attributes are enumerated attributes with the following keywords and states:
application/x-www-form-urlencoded
" keyword and corresponding state.multipart/form-data
" keyword and corresponding state.text/plain
" keyword and corresponding state.The missing value default for these attributes is the application/x-www-form-urlencoded
state.
The enctype of an element is one of those three states. If the element is a submit button and has a formenctype
attribute, then the element's enctype is that attribute's state; otherwise, it is the form owner's enctype
attribute's state.
The target
and formtarget
content attributes, if specified, must have values that are valid browsing context names or keywords.
The target of an element is the value of the element's formtarget
attribute, if the element is a submit button and has such an attribute; or the value of its form owner's target
attribute, if it has such an attribute; or, if the Document
contains a base
element with a target
attribute, then the value of the target
attribute of the first such base
element; or, if there is no such element, the empty string.
The novalidate
and formnovalidate
content attributes are boolean attributes. If present, they indicate that the form is not to be validated during submission.
The no-validate state of an element is true if the element is a submit button and the element's formnovalidate
attribute is present, or if the element's form owner's novalidate
attribute is present, and false otherwise.
This attribute is useful to include "save" buttons on forms that have validation constraints, to allow users to save their progress even though they haven't fully entered the data in the form. The following example shows a simple form that has two required fields. There are three buttons: one to submit the form, which requires both fields to be filled in; one to save the form so that the user can come back and fill it in later; and one to cancel the form altogether.
<form action="editor.cgi" method="post"> <p><label>Name: <input required name=fn></label></p> <p><label>Essay: <textarea required name=essay></textarea></label></p> <p><input type=submit name=submit value="Submit essay"></p> <p><input type=submit formnovalidate name=save value="Save essay"></p> <p><input type=submit formnovalidate name=cancel value="Cancel"></p> </form>
The action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.
A form control dirname
attribute on a form control element enables the submission of the directionality of the element, and gives the name of the field that contains this value during form submission. If such an attribute is specified, its value must not be the empty string.
The input
and textarea
elements define the following members in their DOM interfaces for handling their selection:
void select(); attribute unsigned long selectionStart; attribute unsigned long selectionEnd; attribute DOMString selectionDirection; void setSelectionRange(in unsigned long start, in unsigned long end, in optional DOMString direction);
These methods and attributes expose and control the selection of input
and textarea
text fields.
select
()Selects everything in the text field.
selectionStart
[ = value ]Returns the offset to the start of the selection.
Can be set, to change the start of the selection.
selectionEnd
[ = value ]Returns the offset to the end of the selection.
Can be set, to change the end of the selection.
selectionDirection
[ = value ]Returns the current direction of the selection.
Can be set, to change the direction of the selection.
The possible values are "forward
", "backward
", and "none
".
setSelectionRange
(start, end [, direction] )Changes the selection to cover the given substring in the given direction. If the direction is omitted, it will be reset to be the platform default (none or forward).
Characters with no visible rendering, such as U+200D ZERO WIDTH JOINER, still count as characters. Thus, for instance, the selection can include just an invisible character, and the text insertion cursor can be placed to one side or another of such a character.
To obtain the currently selected text, the following JavaScript suffices:
var selectionText = control.value.substring(control.selectionStart, control.selectionEnd);
To add some text at the start of a text control, while maintaining the text selection, the three attributes must be preserved:
var oldStart = control.selectionStart; var oldEnd = control.selectionEnd; var oldDirection = control.selectionDirection; var prefix = "http://"; control.value = prefix + control.value; control.setSelectionRange(oldStart + prefix.length, oldEnd + prefix.length, oldDirection);
willValidate
Returns true if the element will be validated when the form is submitted; false otherwise.
setCustomValidity
(message)Sets a custom error, so that the element would fail to validate. The given message is the message to be shown to the user when reporting the problem to the user.
If the argument is the empty string, clears the custom error.
validity
. valueMissing
Returns true if the element has no value but is a required field; false otherwise.
validity
. typeMismatch
Returns true if the element's value is not in the correct syntax; false otherwise.
validity
. patternMismatch
Returns true if the element's value doesn't match the provided pattern; false otherwise.
validity
. tooLong
Returns true if the element's value is longer than the provided maximum length; false otherwise.
validity
. rangeUnderflow
Returns true if the element's value is lower than the provided minimum; false otherwise.
validity
. rangeOverflow
Returns true if the element's value is higher than the provided maximum; false otherwise.
validity
. stepMismatch
Returns true if the element's value doesn't fit the rules given by the step
attribute; false otherwise.
validity
. customError
Returns true if the element has a custom error; false otherwise.
validity
. valid
Returns true if the element's value has no validity problems; false otherwise.
checkValidity
()Returns true if the element's value has no validity problems; false otherwise. Fires an invalid
event at the element in the latter case.
validationMessage
Returns the error message that would be shown to the user if the element was to be checked for validity.
In the following example, a script checks the value of a form control each time it is edited, and whenever it is not a valid value, uses the setCustomValidity()
method to set an appropriate message.
<label>Feeling: <input name=f type="text" oninput="check(this)"></label> <script> function check(input) { if (input.value == "good" || input.value == "fine" || input.value == "tired") { input.setCustomValidity('"' + input.value + '" is not a feeling.'); } else { // input is fine -- reset the error message input.setCustomValidity(''); } } </script>
The validity
attribute must return a ValidityState
object that represents the validity states of the element. This object is live, and the same object must be returned each time the element's validity
attribute is retrieved.
Servers should not rely on client-side validation. Client-side validation can be intentionally bypassed by hostile users, and unintentionally bypassed by users of older user agents or automated tools that do not implement these features. The constraint validation features are only intended to improve the user experience, not to provide any kind of security mechanism.
When a form is submitted, the data in the form is converted into the structure specified by the enctype, and then sent to the destination specified by the action using the given method.
For example, take the following form:
<form action="/find.cgi" method=get> <input type=text name=t> <input type=search name=q> <input type=submit> </form>
If the user types in "cats" in the first field and "fur" in the second, and then hits the submit button, then the user agent will load /find.cgi?t=cats&q=fur
.
On the other hand, consider this form:
<form action="/find.cgi" method=post enctype="multipart/form-data"> <input type=text name=t> <input type=search name=q> <input type=submit> </form>
Given the same user input, the result on submission is quite different: the user agent instead does an HTTP POST to the given URL, with as the entity body something like the following text:
------kYFrd4jNJEgCervE Content-Disposition: form-data; name="t" cats ------kYFrd4jNJEgCervE Content-Disposition: form-data; name="q" fur ------kYFrd4jNJEgCervE--
The details, summary, command, and menu elements.
details
elementsummary
element followed by flow content.open
interface HTMLDetailsElement : HTMLElement { attribute boolean open; };
The details
element represents a disclosure widget from which the user can obtain additional information or controls.
The details
element is not appropriate for footnotes. Please see the section on footnotes for details on how to mark up footnotes.
The summary
element child of the element, if any, represents the summary or legend of the details.
The open
content attribute is a boolean attribute. If present, it indicates that the details are to be shown to the user. If the attribute is absent, the details are not to be shown.
The open
IDL attribute must reflect the open
content attribute.
The following example shows the details
element being used to hide technical details in a progress report.
<section class="progress window"> <h1>Copying "Really Achieving Your Childhood Dreams"</h1> <details> <summary>Copying... <progress max="375505392" value="97543282"></progress> 25%</summary> <dl> <dt>Transfer rate:</dt> <dd>452KB/s</dd> <dt>Local filename:</dt> <dd>/home/rpausch/raycd.m4v</dd> <dt>Remote filename:</dt> <dd>/var/www/lectures/raycd.m4v</dd> <dt>Duration:</dt> <dd>01:16:27</dd> <dt>Color profile:</dt> <dd>SD (6-1-6)</dd> <dt>Dimensions:</dt> <dd>320×240</dd> </dl> </details> </section>
The following shows how a details
element can be used to hide some controls by default:
<details> <summary><label for=fn>Name & Extension:</label></summary> <p><input type=text id=fn name=fn value="Pillar Magazine.pdf"> <p><label><input type=checkbox name=ext checked> Hide extension</label> </details>
One could use this in conjunction with other details
in a list to allow the user to collapse a set of fields down to a small set of headings, with the ability to open each one.
In these examples, the summary really just summarises what the controls can change, and not the actual values, which is less than ideal.
summary
elementdetails
element.HTMLElement
.The summary
element represents a summary, caption, or legend for the rest of the contents of the summary
element's parent details
element.
command
elementtype
label
icon
disabled
checked
radiogroup
title
attribute has special semantics on this element.interface HTMLCommandElement : HTMLElement { attribute DOMString type; attribute DOMString label; attribute DOMString icon; attribute boolean disabled; attribute boolean checked; attribute DOMString radiogroup;};
The command
element represents a command that the user can invoke.
A command can be part of a context menu or toolbar, using the menu
element, or can be put anywhere else in the page, to define a keyboard shortcut.
The type
attribute indicates the kind of command: either a normal command with an associated action, or a state or option that can be toggled, or a selection of one item from a list of items.
The attribute is an enumerated attribute with three keywords and states. The "command
" keyword maps to the Command state, the "checkbox
" keyword maps to the Checkbox state, and the "radio
" keyword maps to the Radio state.
The missing value default is the Command state.
The element represents a normal command with an associated action.
The element represents a state or option that can be toggled.
The element represents a selection of one item from a list of items.
The label
attribute gives the name of the command, as shown to the user. The label
attribute must be specified and must have a value that is not the empty string.
The title
attribute gives a hint describing the command, which might be shown to the user to help him.
The icon
attribute gives a picture that represents the command. If the attribute is specified, the attribute's value must contain a valid non-empty URL potentially surrounded by spaces.
The disabled
attribute is a boolean attribute that, if present, indicates that the command is not available in the current state.
The distinction between disabled
and is subtle. A command would be disabled if, in the same context, it could be enabled if only certain aspects of the situation were changed. A command would be marked as hidden if, in that situation, the command will never be enabled. For example, in the context menu for a water faucet, the command "open" might be disabled if the faucet is already open, but the command "eat" would be marked hidden since the faucet could never be eaten.
The checked
attribute is a boolean attribute that, if present, indicates that the command is selected. The attribute must be omitted unless the type
attribute is in either the Checkbox state or the Radio state.
The radiogroup
attribute gives the name of the group of commands that will be toggled when the command itself is toggled, for commands whose type
attribute has the value "radio
". The scope of the name is the child list of the parent element. The attribute must be omitted unless the type
attribute is in the Radio state.
The type
IDL attribute must reflect the content attribute of the same name, limited to only known values.
The label
, icon
, disabled
, checked
, and radiogroup
IDL attributes must reflect the respective content attributes of the same name.
command
elements are not rendered unless they form part of a menu.
Here is an example of a toolbar with three buttons that let the user toggle between left, center, and right alignment. One could imagine such a toolbar as part of a text editor. The toolbar also has a separator followed by another button labeled "Publish", though that button is disabled.
<menu type="toolbar"> <command type="radio" radiogroup="alignment" checked="checked" label="Left" icon="icons/alL.png" onclick="setAlign('left')"> <command type="radio" radiogroup="alignment" label="Center" icon="icons/alC.png" onclick="setAlign('center')"> <command type="radio" radiogroup="alignment" label="Right" icon="icons/alR.png" onclick="setAlign('right')"> <hr> <command type="command" disabled label="Publish" icon="icons/pub.png" onclick="publish()"> </menu>
menu
elementtype
attribute is in the toolbar state: Interactive content.li
elements.type
label
interface HTMLMenuElement : HTMLElement { attribute DOMString type; attribute DOMString label; };
The menu
element represents a list of commands.
The type
attribute is an enumerated attribute indicating the kind of menu being declared. The attribute has three states. The context
keyword maps to the context menu state, in which the element is declaring a context menu. The toolbar
keyword maps to the toolbar state, in which the element is declaring a toolbar. The attribute may also be omitted. The missing value default is the list state, which indicates that the element is merely a list of commands that is neither declaring a context menu nor
defining a toolbar.
If a menu
element's type
attribute is in the context menu state, then the element represents the commands of a context menu, and the user can only interact with the commands if that context menu is activated.
If a menu
element's type
attribute is in the toolbar state, then the element represents a list of active commands that the user can immediately interact with.
If a menu
element's type
attribute is in the list state, then the element either represents an unordered list of items (each represented by an li
element), each of which represents a command that the user can perform or activate, or, if the element has no li
element children, flow content describing available commands.
The label
attribute gives the label of the menu. It is used by user agents to display nested menus in the UI. For example, a context menu containing another menu would use the nested menu's label
attribute for the submenu's menu label.
The type
and label
IDL attributes must reflect the respective content attributes of the same name.
The menu
element is used to define context menus and toolbars.
For example, the following represents a toolbar with three menu buttons on it, each of which has a dropdown menu with a series of options:
<menu type="toolbar"> <li> <menu label="File"> <button type="button" onclick="fnew()">New...</button> <button type="button" onclick="fopen()">Open...</button> <button type="button" onclick="fsave()">Save</button> <button type="button" onclick="fsaveas()">Save as...</button> </menu> </li> <li> <menu label="Edit"> <button type="button" onclick="ecopy()">Copy</button> <button type="button" onclick="ecut()">Cut</button> <button type="button" onclick="epaste()">Paste</button> </menu> </li> <li> <menu label="Help"> <li><a href="help.html">Help</a></li> <li><a href="about.html">About</a></li> </menu> </li> </menu>
In a supporting user agent, this might look like this:
In a legacy user agent, the above would look like a bulleted list with three items, the first of which has four buttons, the second of which has three, and the third of which has two nested bullet points with two items consisting of links.
The following implements a similar toolbar, with a single button whose values, when selected, redirect the user to Web sites.
<form action="redirect.cgi"> <menu type="toolbar"> <label for="goto">Go to...</label> <menu label="Go"> <select id="goto"> <option value="" selected="selected"> Select site: </option> <option value="http://www.apple.com/"> Apple </option> <option value="http://www.mozilla.org/"> Mozilla </option> <option value="http://www.opera.com/"> Opera </option> </select> <span><input type="submit" value="Go"></span> </menu> </menu> </form>
The behavior in supporting user agents is similar to the example above, but here the legacy behavior consists of a single select
element with a submit button. The submit button doesn't appear in the toolbar, because it is not a direct child of the menu
element or of its li
children.
The contextmenu
attribute gives the element's context menu. The value must be the ID of a menu
element in the DOM.
The contextMenu
IDL attribute must reflect the contextmenu
content attribute.
Here is an example of a context menu for an input control:
<form name="npc"> <label>Character name: <input name=char type=text contextmenu=namemenu required></label> <menu type=context id=namemenu> <command label="Pick random name" onclick="document.forms.npc.elements.char.value = getRandomName()"> <command label="Prefill other fields based on name" onclick="prefillFields(document.forms.npc.elements.char.value)"> </menu> </form>
This adds two items to the control's context menu, one called "Pick random name", and one called "Prefill other fields based on name". They invoke scripts that are not shown in the example above.
A command is the abstraction behind menu items, buttons, and links.
Commands are defined to have the following facets:
These facets are exposed on elements using the command API:
commandType
Exposes the Type facet of the command.
id
Exposes the ID facet of the command.
label
Exposes the Label facet of the command.
title
Exposes the Hint facet of the command.
icon
Exposes the Icon facet of the command.
accessKeyLabel
Exposes the Access Key facet of the command.
hidden
Exposes the state of the element's attribute, which is generally equivalent to the facet of the command. For
label
and legend
elements (used in conjunction with the accesskey
attribute), the facet is derived from another element (the one that the assigned
access key will trigger), and cannot be directly accessed from the element.
disabled
Exposes the Disabled State facet of the command.
checked
Exposes the Checked State facet of the command.
click
()Triggers the Action of the command.
commands
Returns an HTMLCollection
of the elements in the Document
that define commands and have IDs.
User agents may expose the commands whose facet is false (visible), e.g. in the user agent's menu bar. User agents are encouraged to do this especially for commands that have Access Keys, as a way to advertise those keys to the user.
Links are a conceptual construct, created by a
, area
, and link
elements, that represent a connection between two resources, one of which is the current Document
. There are two kinds of links in HTML:
These are links to resources that are to be used to augment the current document, generally automatically processed by the user agent.
These are links to other resources that are generally exposed to the user by the user agent so that the user can cause the user agent to navigate to those resources, e.g. to visit them in a browser or download them.
For link
elements with an href
attribute and a rel
attribute, links must be created for the keywords of the rel
attribute, as defined for those keywords in the link types section.
Similarly, for a
and area
elements with an href
attribute and a rel
attribute, links must be created for the keywords of the rel
attribute as defined for those keywords in the link types section. Unlike link
elements, however, a
and area
element with an href
attribute that either do not have a rel
attribute, or whose rel
attribute has no keywords that are defined as specifying hyperlinks, must also create a hyperlink. This implied hyperlink has no special meaning (it has no link type) beyond linking the element's document to the resource given by the element's href
attribute.
A hyperlink can have one or more hyperlink annotations that modify the processing semantics of that hyperlink.
a
and area
elementsThe href
attribute on a
and area
elements must have a value that is a valid URL potentially surrounded by spaces.
The href
attribute on a
and area
elements is not required; when those elements do not have href
attributes they do not create hyperlinks.
The target
attribute, if present, must be a valid browsing context name or keyword. It gives the name of the browsing context that will be used.
The rel
attribute on a
and area
elements controls what kinds of links the elements create. The attribue's value must be a set of space-separated tokens. The allowed keywords and their meanings are defined below.
The rel
attribute has no default value. If the attribute is omitted or if none of the values in the attribute are recognized by the user agent, then the document has no particular relationship with the destination resource other than there being a hyperlink between the two.
The media
attribute describes for which media the target document was designed. It is purely advisory. The value must be a valid media query. The default, if the media
attribute is omitted, is "all
".
The hreflang
attribute on a
and area
elements that create hyperlinks, if present, gives the language of the linked resource. It is purely advisory. The value must be a valid BCP 47 language tag. [BCP47]
The type
attribute, if present, gives the MIME type of the linked resource. It is purely advisory. The value must be a valid MIME type.
The following table summarizes the link types that are defined by this specification. This table is non-normative; the actual definitions for the link types are given in the next few sections.
In this section, the term referenced document refers to the resource identified by the element representing the link, and the term current document refers to the resource within which the element representing the link finds itself.
Except where otherwise specified, a keyword must not be specified more than once per rel
attribute.
The link types that contain no U+003A COLON characters (:), including all those defined in this specification, are ASCII case-insensitive values.
Thus, rel="next"
is the same as rel="NEXT"
.
Link type | Effect on... | Brief description | |
---|---|---|---|
link |
a and area |
||
alternate |
Hyperlink | Hyperlink | Gives alternate representations of the current document. |
author |
Hyperlink | Hyperlink | Gives a link to the current document's author. |
bookmark |
not allowed | Hyperlink | Gives the permalink for the nearest ancestor section. |
external |
not allowed | Hyperlink | Indicates that the referenced document is not part of the same site as the current document. |
help |
Hyperlink | Hyperlink | Provides a link to context-sensitive help. |
icon |
External Resource | not allowed | Imports an icon to represent the current document. |
license |
Hyperlink | Hyperlink | Indicates that the main content of the current document is covered by the copyright license described by the referenced document. |
next |
Hyperlink | Hyperlink | Indicates that the current document is a part of a series, and that the next document in the series is the referenced document. |
nofollow |
not allowed | Annotation | Indicates that the current document's original author or publisher does not endorse the referenced document. |
noreferrer |
not allowed | Annotation | Requires that the user agent not send an HTTP Referer (sic) header if the user follows the hyperlink. |
pingback |
External Resource | not allowed | Gives the address of the pingback server that handles pingbacks to the current document. |
prefetch |
External Resource | External Resource | Specifies that the target resource should be preemptively cached. |
prev |
Hyperlink | Hyperlink | Indicates that the current document is a part of a series, and that the previous document in the series is the referenced document. |
search |
Hyperlink | Hyperlink | Gives a link to a resource that can be used to search through the current document and its related pages. |
sidebar |
Hyperlink | Hyperlink | Specifies that the referenced document, if retrieved, is intended to be shown in the browser's sidebar (if it has one). |
stylesheet |
External Resource | not allowed | Imports a stylesheet. |
tag |
Hyperlink | Hyperlink | Gives a tag (identified by the given address) that applies to the current document. |
alternate
"The alternate
keyword may be used with link
, a
, and area
elements.
The meaning of this keyword depends on the values of the other attributes.
link
element and the rel
attribute also contains the keyword stylesheet
The alternate
keyword modifies the meaning of the stylesheet
keyword in the way described for that keyword. The alternate
keyword does not create a link of its own.
alternate
keyword is used with the type
attribute set to the value application/rss+xml
or the value application/atom+xml
The keyword creates a hyperlink referencing a syndication feed (though not necessarily syndicating exactly the same content as the current page).
The keyword creates a hyperlink referencing an alternate representation of the current document.
The nature of the referenced document is given by the media
, hreflang
, and type
attributes.
If the alternate
keyword is used with the media
attribute, it indicates that the referenced document is intended for use with the media specified.
If the alternate
keyword is used with the hreflang
attribute, and that attribute's value differs from the root element's language, it indicates that the referenced document is a translation.
If the alternate
keyword is used with the type
attribute, it indicates that the referenced document is a reformulation of the current document in the specified format.
The media
, hreflang
, and type
attributes can be combined when specified with the alternate
keyword.
For example, the following link is a French translation that uses the PDF format:
<link rel=alternate type=application/pdf hreflang=fr href=manual-fr>
This relationship is transitive — that is, if a document links to two other documents with the link type "alternate
", then, in addition to implying that those documents are alternative representations of the first document, it is also implying that those two documents are alternative representations of each other.
author
"The author
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
For a
and area
elements, the author
keyword indicates that the referenced document provides further information about the author of the nearest article
element ancestor of the element defining the hyperlink, if there is one, or of the page as a whole, otherwise.
For link
elements, the author
keyword indicates that the referenced document provides further information about the author for the page as a whole.
The "referenced document" can be, and often is, a mailto:
URL giving the e-mail address of the author. [MAILTO]
bookmark
"The bookmark
keyword may be used with a
and area
elements. This keyword creates a hyperlink.
The bookmark
keyword gives a permalink for the nearest ancestor article
element of the linking element in question, or of the section the linking element is most closely associated with, if there are no ancestor article
elements.
The following snippet has three permalinks. A user agent could determine which permalink applies to which part of the spec by looking at where the permalinks are given.
... <body> <h1>Example of permalinks</h1> <div id="a"> <h2>First example</h2> <p><a href="a.html" rel="bookmark">This</a> permalink applies to only the content from the first H2 to the second H2. The DIV isn't exactly that section, but it roughly corresponds to it.</p> </div> <h2>Second example</h2> <article id="b"> <p><a href="b.html" rel="bookmark">This</a> permalink applies to the outer ARTICLE element (which could be, e.g., a blog post).</p> <article id="c"> <p><a href="c.html" rel="bookmark">This</a> permalink applies to the inner ARTICLE element (which could be, e.g., a blog comment).</p> </article> </article> </body> ...
external
"The external
keyword may be used with a
and area
elements. This keyword creates a hyperlink.
The external
keyword indicates that the link is leading to a document that is not part of the site that the current document forms a part of.
help
"The help
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
For a
and area
elements, the help
keyword indicates that the referenced document provides further help information for the parent of the element defining the hyperlink, and its children.
In the following example, the form control has associated context-sensitive help. The user agent could use this information, for example, displaying the referenced document if the user presses the "Help" or "F1" key.
<p><label> Topic: <input name=topic> <a href="help/topic.html" rel="help">(Help)</a></label></p>
For link
elements, the help
keyword indicates that the referenced document provides help for the page as a whole.
icon
"The icon
keyword may be used with link
elements. This keyword creates an external resource link.
Icons could be auditory icons, visual icons, or other kinds of icons.
The sizes
attribute gives the sizes of icons for visual media.
If specified, the attribute must have a value that is an unordered set of unique space-separated tokens, which are ASCII case-insensitive. The values must all be either an ASCII case-insensitive match for the string "any
", or a value that consists of two valid non-negative integers that do not have a leading U+0030 DIGIT ZERO (0) character and that are separated by a single U+0078 LATIN SMALL LETTER X or U+0058 LATIN CAPITAL LETTER X character.
The keywords represent icon sizes.
The any
keyword represents that the resource contains a scalable icon, e.g. as provided by an SVG image.
The keywords specified on the sizes
attribute must not represent icon sizes that are not actually available in the linked resource.
The following snippet shows the top part of an application with several icons.
<!DOCTYPE HTML> <html> <head> <title>lsForums — Inbox</title> <link rel=icon href=favicon.png sizes="16x16" type="image/png"> <link rel=icon href=windows.ico sizes="32x32 48x48" type="image/vnd.microsoft.icon"> <link rel=icon href=mac.icns sizes="128x128 512x512 8192x8192 32768x32768"> <link rel=icon href=iphone.png sizes="57x57" type="image/png"> <link rel=icon href=gnome.svg sizes="any" type="image/svg+xml"> <link rel=stylesheet href=lsforums.css> <script src=lsforums.js></script> <meta name=application-name content="lsForums"> </head> <body> ...
license
"The license
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
The license
keyword indicates that the referenced document provides the copyright license terms under which the main content of the current document is provided.
This specification does not specify how to distinguish between the main content of a document and content that is not deemed to be part of that main content. The distinction should be made clear to the user.
Consider a photo sharing site. A page on that site might describe and show a photograph, and the page might be marked up as follows:
<!DOCTYPE HTML> <html> <head> <title>Exampl Pictures: Kissat</title> <link rel="stylesheet" href="/style/default"> </head> <body> <h1>Kissat</h1> <nav> <a href="../">Return to photo index</a> </nav> <figure> <img src="/pix/39627052_fd8dcd98b5.jpg"> <figcaption>Kissat</figcaption> </figure> <p>One of them has six toes!</p> <p><small><a rel="license" href="http://www.opensource.org/licenses/mit-license.php">MIT Licensed</a></small></p> <footer> <a href="/">Home</a> | <a href="../">Photo index</a> <p><small>© copyright 2009 Exampl Pictures. All Rights Reserved.</small></p> </footer> </body> </html>
In this case the license
applies to just the photo (the main content of the document), not the whole document. In particular not the design of the page itself, which is covered by the copyright given at the bottom of the document. This could be made clearer in the styling (e.g. making the license link prominently positioned near the photograph, while having the page copyright in light small text at the foot of the page.
nofollow
"The nofollow
keyword may be used with a
and area
elements. This keyword does not create a hyperlink, but annotates any other hyperlinks created by the element (the implied hyperlink, if no other keywords create one).
The nofollow
keyword indicates that the link is not endorsed by the original author or publisher of the page, or that the link to the referenced document was included primarily because of a commercial relationship between people affiliated with the two pages.
noreferrer
"The noreferrer
keyword may be used with a
and area
elements. This keyword does not create a hyperlink, but annotates any other hyperlinks created by the element (the implied hyperlink, if no other keywords create one).
It indicates that no referrer information is to be leaked when following the link.
pingback
"The pingback
keyword may be used with link
elements. This keyword creates an external resource link.
For the semantics of the pingback
keyword, see the Pingback 1.0 specification. [PINGBACK]
prefetch
"The prefetch
keyword may be used with link
, a
, and area
elements. This keyword creates an external resource link.
The prefetch
keyword indicates that preemptively fetching and caching the specified resource is likely to be beneficial, as it is highly likely that the user will require this resource.
There is no default type for resources given by the prefetch
keyword.
search
"The search
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
The search
keyword indicates that the referenced document provides an interface specifically for searching the document and its related resources.
OpenSearch description documents can be used with link
elements and the search
link type to enable user agents to autodiscover search interfaces. [OPENSEARCH]
sidebar
"The sidebar
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
The sidebar
keyword indicates that the referenced document, if retrieved, is intended to be shown in a secondary browsing context (if possible), instead of in the current browsing context.
A hyperlink with the sidebar
keyword specified is a sidebar hyperlink.
stylesheet
"The stylesheet
keyword may be used with link
elements. This keyword creates an external resource link that contributes to the styling processing model.
The specified resource is a resource that describes how to present the document. Exactly how the resource is to be processed depends on the actual type of the resource.
If the alternate
keyword is also specified on the link
element, then the link is an alternative stylesheet; in this case, the title
attribute must be specified on the link
element, with a non-empty value.
The default type for resources given by the stylesheet
keyword is text/css
.
tag
"The tag
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
The tag
keyword indicates that the tag that the referenced document represents applies to the current document.
Since it indicates that the tag applies to the current document, it would be inappropriate to use this keyword in the markup of a tag cloud, which lists the popular tag across a set of pages.
Some documents form part of a sequence of documents.
A sequence of documents is one where each document can have a previous sibling and a next sibling. A document with no previous sibling is the start of its sequence, a document with no next sibling is the end of its sequence.
A document may be part of multiple sequences.
next
"The next
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
The next
keyword indicates that the document is part of a sequence, and that the link is leading to the document that is the next logical document in the sequence.
prev
"The prev
keyword may be used with link
, a
, and area
elements. This keyword creates a hyperlink.
The prev
keyword indicates that the document is part of a sequence, and that the link is leading to the document that is the previous logical document in the sequence.
Extensions to the predefined set of link types may be registered in the Microformats wiki existing-rel-values page. [MFREL]
Anyone is free to edit the Microformats wiki existing-rel-values page at any time to add a type. Extension types must be specified with the following information:
The actual value being defined. The value should not be confusingly similar to any other defined value (e.g. differing only in case).
If the value contains a U+003A COLON character (:), it must also be an absolute URL.
link
One of the following:
link
elements.link
element; it creates a hyperlink.link
element; it creates an external resource link.a
and area
One of the following:
a
and area
elements.a
and area
elements; it creates a hyperlink.a
and area
elements; it creates an external resource link.a
and area
elements; it annotates other hyperlinks created by the element.A short non-normative description of what the keyword's meaning is.
A link to a more detailed description of the keyword's semantics and requirements. It could be another page on the Wiki, or a link to an external page.
A list of other keyword values that have exactly the same processing requirements. Authors should not use the values defined to be synonyms, they are only intended to allow user agents to support legacy content. Anyone may remove synonyms that are not used in practice; only names that need to be processed as synonyms for compatibility with legacy content are to be registered in this way.
One of the following:
If a keyword is found to be redundant with existing values, it should be removed and listed as a synonym for the existing value.
If a keyword is registered in the "proposed" state for a period of a month or more without being used or specified, then it may be removed from the registry.
If a keyword is added with the "proposed" status and found to be redundant with existing values, it should be removed and listed as a synonym for the existing value. If a keyword is added with the "proposed" status and found to be harmful, then it should be changed to "discontinued" status.
Anyone can change the status at any time, but should only do so in accordance with the definitions above.
Types defined as extensions in the Microformats wiki existing-rel-values page with the status "proposed" or "ratified" may be used with the rel
attribute on link
, a
, and area
elements in accordance to the "Effect on..." field. [MFREL]
The main content of a page — not including headers and footers, navigation links, sidebars, advertisements, and so forth — can be marked up in a variety of ways, depending on the needs of the author.
The simplest solution is to not mark up the main content at all, and just leave it as implicit. Another way to think of this is that the body
elements marks up the main content of the page, and the bits that aren't main content are excluded through the use of more appropriate elements like aside
and nav
.
Here is a short Web page marked up along this minimalistic school of thought. The main content is highlighted. Notice how all the other content in the body
is marked up with elements to indicate that it's not part of the main content, in this case header
, nav
, and footer
.
<!DOCTYPE HTML> <html> <head> <title> My Toys </title> </head> <body> <header> <h1>My toys</h1> </header> <nav> <p><a href="/">Home</a></p> <p><a href="/contact">Contact</a></p> </nav> <p>I really like my chained book and my telephone. I'm not such a fan of my big ball.</p> <p>Another toy I like is my mirror.</p> <footer> <p>© copyright 2010 by the boy</p> </footer> </body> </html>
If the main content is an independent unit of content that one could imagine syndicating independently, then the article
element would be appropriate to mark up the main content of the document.
The document in the previous example is here recast as a blog post:
<!DOCTYPE HTML> <html> <head> <title> The Boy Blog: My Toys </title> </head> <body> <header> <h1>The Boy Blog</h1> </header> <nav> <p><a href="/">Home</a></p> <p><a href="/contact">Contact</a></p> </nav> <article> <header> <h1>My toys</h1> <p>Published <time pubdate datetime="2010-08-04">August 4th</time></p> </header> <p>I really like my chained book and my telephone. I'm not such a fan of my big ball.</p> <p>Another toy I like is my mirror.</p> </article> <footer> <p>© copyright 2010 by the boy</p> </footer> </body> </html>
If the main content is not an independent unit of content so much as a section of a larger work, for instance a chapter, then the section
element would be appropriate to mark up the main content of the document.
Here is the same document, case as a chapter in an online book:
<!DOCTYPE HTML> <html> <head> <title> Chapter 2: My Toys — The Book of the Boy </title> </head> <body> <header> <h1>Chapter 2: My Toys</h1> </header> <nav> <p><a href="/">Front Page</a></p> <p><a href="/toc">Table of Contents</a></p> <p><a href="/c1">Chapter 1</a> — <a href="/c3">Chapter 3</a></p> </nav> <section> <p>I really like my chained book and my telephone. I'm not such a fan of my big ball.</p> <p>Another toy I like is my mirror.</p> </section> <footer> <p>© copyright 2010 by the boy</p> </footer> </body> </html>
If neither article
nor section
would be appropriate, but the main content still needs an explicit element, for example for styling purposes, then the div
element can be used.
This is the same as the original example, but using div
for the main content instead of leaving it implied:
<!DOCTYPE HTML> <html> <head> <title> My Toys </title> <style> body > div { background: navy; color: yellow; } </style> </head> <body> <header> <h1>My toys</h1> </header> <nav> <p><a href="/">Home</a></p> <p><a href="/contact">Contact</a></p> </nav> <div> <p>I really like my chained book and my telephone. I'm not such a fan of my big ball.</p> <p>Another toy I like is my mirror.</p> </div> <footer> <p>© copyright 2010 by the boy</p> </footer> </body> </html>
This specification does not provide a machine-readable way of describing bread-crumb navigation menus. Authors are encouraged to just use a series of links in a paragraph. The nav
element can be used to mark the section containing these paragraphs as being navigation blocks.
In the following example, the current page can be reached via two paths.
<nav> <p> <a href="/">Main</a> > <a href="/products/">Products</a> > <a href="/products/dishwashers/">Dishwashers</a> > <a>Second hand</a> </p> <p> <a href="/">Main</a> > <a href="/second-hand/">Second hand</a> > <a>Dishwashers</a> </p> </nav>
This specification does not define any markup specifically for marking up lists of keywords that apply to a group of pages (also known as tag clouds). In general, authors are encouraged to either mark up such lists using ul
elements with explicit inline counts that are then hidden and turned into a presentational effect using a style sheet, or to use SVG.
Here, three tags are included in a short tag cloud:
<style> @media screen, print, handheld, tv { /* should be ignored by non-visual browsers */ .tag-cloud > li > span { display: none; } .tag-cloud > li { display: inline; } .tag-cloud-1 { font-size: 0.7em; } .tag-cloud-2 { font-size: 0.9em; } .tag-cloud-3 { font-size: 1.1em; } .tag-cloud-4 { font-size: 1.3em; } .tag-cloud-5 { font-size: 1.5em; } } </style> ... <ul class="tag-cloud"> <li class="tag-cloud-4"><a title="28 instances" href="/t/apple">apple</a> <span>(popular)</span> <li class="tag-cloud-2"><a title="6 instances" href="/t/kiwi">kiwi</a> <span>(rare)</span> <li class="tag-cloud-5"><a title="41 instances" href="/t/pear">pear</a> <span>(very popular)</span> </ul>
The actual frequency of each tag is given using the title
attribute. A CSS style sheet is provided to convert the markup into a cloud of differently-sized words, but for user agents that do not support CSS or are not visual, the markup contains annotations like "(popular)" or "(rare)" to categorize the various tags by frequency, thus enabling all users to benefit from the information.
The ul
element is used (rather than ol
) because the order is not particularly important: while the list is in fact ordered alphabetically, it would convey the same information if ordered by, say, the length of the tag.
The tag
rel
-keyword is not used on these a
elements because they do not represent tags that apply to the page itself; they are just part of an index listing the tags themselves.
This specification does not define a specific element for marking up conversations, meeting minutes, chat transcripts, dialogues in screenplays, instant message logs, and other situations where different players take turns in discourse.
Instead, authors are encouraged to mark up conversations using p
elements and punctuation. Authors who need to mark the speaker for styling purposes are encouraged to use span
or b
. Paragraphs with their text wrapped in the i
element can be used for marking up stage directions.
This example demonstrates this using an extract from Abbot and Costello's famous sketch, Who's on first:
<p> Costello: Look, you gotta first baseman? <p> Abbott: Certainly. <p> Costello: Who's playing first? <p> Abbott: That's right. <p> Costello becomes exasperated. <p> Costello: When you pay off the first baseman every month, who gets the money? <p> Abbott: Every dollar of it.
The following extract shows how an IM conversation log could be marked up.
<p> <time>14:22</time> <b>egof</b> I'm not that nerdy, I've only seen 30% of the star trek episodes <p> <time>14:23</time> <b>kaj</b> if you know what percentage of the star trek episodes you have seen, you are inarguably nerdy <p> <time>14:23</time> <b>egof</b> it's unarguably <p> <time>14:23</time> <i>* kaj blinks</i> <p> <time>14:24</time> <b>kaj</b> you are not helping your case
HTML does not have a dedicated mechanism for marking up footnotes. Here are the recommended alternatives.
For short inline annotations, the title
attribute should be used.
In this example, two parts of a dialogue are annotated with footnote-like content using the title
attribute.
<p> <b>Customer</b>: Hello! I wish to register a complaint. Hello. Miss? <p> <b>Shopkeeper</b>: <span title="Colloquial pronunciation of 'What do you'" >Watcha</span> mean, miss? <p> <b>Customer</b>: Uh, I'm sorry, I have a cold. I wish to make a complaint. <p> <b>Shopkeeper</b>: Sorry, <span title="This is, of course, a lie.">we're closing for lunch</span>.
For longer annotations, the a
element should be used, pointing to an element later in the document. The convention is that the contents of the link be a number in square brackets.
In this example, a footnote in the dialogue links to a paragraph below the dialogue. The paragraph then reciprocally links back to the dialogue, allowing the user to return to the location of the footnote.
<p> Announcer: Number 16: The <i>hand</i>. <p> Interviewer: Good evening. I have with me in the studio tonight Mr Norman St John Polevaulter, who for the past few years has been contradicting people. Mr Polevaulter, why <em>do</em> you contradict people? <p> Norman: I don't. <sup><a href="#fn1" id="r1">[1]</a></sup> <p> Interviewer: You told me you did! ... <section> <p id="fn1"><a href="#r1">[1]</a> This is, naturally, a lie, but paradoxically if it were true he could not say so without contradicting the interviewer and thus making it false.</p> </section>
For side notes, longer annotations that apply to entire sections of the text rather than just specific words or sentences, the aside
element should be used.
In this example, a sidebar is given after a dialogue, giving it some context.
<p> <span class="speaker">Customer</span>: I will not buy this record, it is scratched. <p> <span class="speaker">Shopkeeper</span>: I'm sorry? <p> <span class="speaker">Customer</span>: I will not buy this record, it is scratched. <p> <span class="speaker">Shopkeeper</span>: No no no, this's'a tobacconist's. <aside> <p>In 1970, the British Empire lay in ruins, and foreign nationalists frequented the streets — many of them Hungarians (not the streets — the foreign nationals). Sadly, Alexander Yalt has been publishing incompetently-written phrase books. </aside>
For figures or tables, footnotes can be included in the relevant figcaption
or caption
element, or in surrounding prose.
In this example, a table has cells with footnotes that are given in prose. A figure
element is used to give a single legend to the combination of the table and its footnotes.
<figure> <figcaption>Table 1. Alternative activities for knights.</figcaption> <table> <tr> <th> Activity <th> Location <th> Cost <tr> <td> Dance <td> Wherever possible <td> £0<sup><a href="#fn1">1</a></sup> <tr> <td> Routines, chorus scenes<sup><a href="#fn2">2</a></sup> <td> Undisclosed <td> Undisclosed <tr> <td> Dining<sup><a href="#fn3">3</a></sup> <td> Camelot <td> Cost of ham, jam, and spam<sup><a href="#fn4">4</a></sup> </table> <p id="fn1">1. Assumed.</p> <p id="fn2">2. Footwork impeccable.</p> <p id="fn3">3. Quality described as "well".</p> <p id="fn4">4. A lot.</p> </figure>
A browsing context is an environment in which Document
objects are presented to the user.
A tab or window in a Web browser typically contains a browsing context, as does an iframe
.
Each browsing context has a corresponding WindowProxy
object.
A browsing context has a session history, which lists the Document
objects that that browsing context has presented, is presenting, or will present. At any time, one Document
in each browsing context is designated the active document.
Each Document
is associated with a Window
object. A browsing context's WindowProxy
object forwards everything to the browsing context's active document's Window
object.
In general, there is a 1-to-1 mapping from the Window
object to the Document
object. In one particular case, a Window
can be reused for the presentation of a second Document
in the same browsing context, such that the mapping is then 2-to-1. This occurs when a browsing context is navigated from the initial about:blank
Document
to another, with replacement enabled.
A Document
does not necessarily have a browsing context associated with it. In particular, data mining tools are likely to never instantiate browsing contexts.
A browsing context can have a creator browsing context, the browsing context that was responsible for its creation. If a browsing context has a parent browsing context, then that is its creator browsing context. Otherwise, if the browsing context has an opener browsing context, then that is its creator browsing context. Otherwise, the browsing context has no creator browsing context.
If a browsing context A has a creator browsing context, then the Document
that was the active document of that creator browsing context at the time A was created is the creator Document
.
Certain elements (for example, iframe
elements) can instantiate further browsing contexts. These are called nested browsing contexts. If a browsing context P has a Document
s D with an element E that nests another browsing context C inside it, then C is said to be nested through D, and E is said to be the browsing context container of C. If the browsing context container element E is in the Document
D, then P is said to be the parent browsing context of C and C is said to be a child browsing context of P. Otherwise, the nested browsing context C has no parent browsing context.
A browsing context A is said to be an ancestor of a browsing context B if there exists a browsing context A' that is a child browsing context of A and that is itself an ancestor of B, or if there is a browsing context P that is a child browsing context of A and that is the parent browsing context of B.
A browsing context that is not a nested browsing context has no parent browsing context, and is the top-level browsing context of all the browsing contexts for which it is an ancestor browsing context.
The transitive closure of parent browsing contexts for a nested browsing context gives the list of ancestor browsing contexts.
The list of the descendant browsing contexts of a Document
d is the (ordered) list returned by the following algorithm:
Let list be an empty list.
For each child browsing context of d that is nested through an element that is in the Document
d, in the tree order of the elements nesting those browsing contexts, run these substeps:
Append that child browsing context to the list list.
Append the list of the descendant browsing contexts of the active document of that child browsing context to the list list.
Return the constructed list.
A Document
is said to be fully active when it is the active document of its browsing context, and either its browsing context is a top-level browsing context, or it has a parent browsing context and the Document
through which it is nested is itself fully active.
Because they are nested through an element, child browsing contexts are always tied to a specific Document
in their parent browsing context. User agents must not allow the user to interact with child browsing contexts of elements that are in Document
s that are not themselves fully active.
A nested browsing context can have a seamless browsing context flag set, if it is embedded through an iframe
element with a seamless
attribute.
A nested browsing context can in some cases be taken out of its parent browsing context (e.g. if an iframe
element is removed from its Document
). In such a situation, the nested browsing context has no parent browsing context, but it still has the same browsing context container and is still nested through that element's Document
. Such a nested browsing context is not a top-level browsing context, and cannot contain Document
s that are fully active. Furthermore, if a browsing context container (such as an iframe
) is moved to another Document
, then the parent browsing context of its nested browsing context will change.
top
Returns the WindowProxy
for the top-level browsing context.
parent
Returns the WindowProxy
for the parent browsing context.
frameElement
Returns the Element
for the browsing context container.
Returns null if there isn't one.
Throws a SECURITY_ERR
exception in cross-origin situations.
It is possible to create new browsing contexts that are related to a top-level browsing context without being nested through an element. Such browsing contexts are called auxiliary browsing contexts. Auxiliary browsing contexts are always top-level browsing contexts.
An auxiliary browsing context has an opener browsing context, which is the browsing context from which the auxiliary browsing context was created.
The opener
IDL attribute on the Window
object, on getting, must return the WindowProxy
object of the browsing context from which the current browsing context was created (its opener browsing context), if there is one, if it is still available, and if the current browsing context has not disowned its opener. On setting, if the new value is null then the
current browsing context must disown its opener; if the new value is anything else then the user agent must ignore the new value.
User agents may support secondary browsing contexts, which are browsing contexts that form part of the user agent's interface, apart from the main content area.
Browsing contexts can have a browsing context name. By default, a browsing context has no name (its name is not set).
A valid browsing context name is any string with at least one character that does not start with a U+005F LOW LINE character. (Names starting with an underscore are reserved for special keywords.)
A valid browsing context name or keyword is any string that is either a valid browsing context name or that is an ASCII case-insensitive match for one of: _blank
, _self
, _parent
, or _top
.
Window
object[ReplaceableNamedProperties] interface Window { // the current browsing context readonly attribute WindowProxy window; readonly attribute WindowProxy self; readonly attribute Document document; attribute DOMString name; [PutForwards=href] readonly attribute Location location; readonly attribute History history; [Replaceable] readonly attribute BarProp locationbar; [Replaceable] readonly attribute BarProp menubar; [Replaceable] readonly attribute BarProp personalbar; [Replaceable] readonly attribute BarProp scrollbars; [Replaceable] readonly attribute BarProp statusbar; [Replaceable] readonly attribute BarProp toolbar; void close(); void stop(); void focus(); void blur(); // other browsing contexts [Replaceable] readonly attribute WindowProxy frames; [Replaceable] readonly attribute unsigned long length; readonly attribute WindowProxy top; attribute WindowProxy opener; readonly attribute WindowProxy parent; readonly attribute Element frameElement; WindowProxy open(in optional DOMString url, in optional DOMString target, in optional DOMString features, in optional DOMString replace); getter WindowProxy (in unsigned long index); getter any (in DOMString name); // the user agent readonly attribute Navigator navigator; readonly attribute ApplicationCache applicationCache; // user prompts void alert(in DOMString message); boolean confirm(in DOMString message); DOMString prompt(in DOMString message, in optional DOMString default); void print(); any showModalDialog(in DOMString url, in optional any argument); // event handler IDL attributes attribute Function onabort; attribute Function onafterprint; attribute Function onbeforeprint; attribute Function onbeforeunload; attribute Function onblur; attribute Function oncanplay; attribute Function oncanplaythrough; attribute Function onchange; attribute Function onclick; attribute Function oncontextmenu; attribute Function oncuechange; attribute Function ondblclick; attribute Function ondrag; attribute Function ondragend; attribute Function ondragenter; attribute Function ondragleave; attribute Function ondragover; attribute Function ondragstart; attribute Function ondrop; attribute Function ondurationchange; attribute Function onemptied; attribute Function onended; attribute Function onerror; attribute Function onfocus; attribute Function onhashchange; attribute Function oninput; attribute Function oninvalid; attribute Function onkeydown; attribute Function onkeypress; attribute Function onkeyup; attribute Function onload; attribute Function onloadeddata; attribute Function onloadedmetadata; attribute Function onloadstart; attribute Function onmessage; attribute Function onmousedown; attribute Function onmousemove; attribute Function onmouseout; attribute Function onmouseover; attribute Function onmouseup; attribute Function onmousewheel; attribute Function onoffline; attribute Function ononline; attribute Function onpause; attribute Function onplay; attribute Function onplaying; attribute Function onpagehide; attribute Function onpageshow; attribute Function onpopstate; attribute Function onprogress; attribute Function onratechange; attribute Function onreadystatechange; attribute Function onredo; attribute Function onreset; attribute Function onresize; attribute Function onscroll; attribute Function onseeked; attribute Function onseeking; attribute Function onselect; attribute Function onshow; attribute Function onstalled; attribute Function onstorage; attribute Function onsubmit; attribute Function onsuspend; attribute Function ontimeupdate; attribute Function onundo; attribute Function onunload; attribute Function onvolumechange; attribute Function onwaiting; }; Window implements EventTarget;
window
frames
self
These attributes all return window.
document
Returns the active document.
defaultView
Returns the Window
object of the active document.
open
( [ url [, target [, features [, replace ] ] ] ] )Opens a window to show url (defaults to about:blank
), and returns it. The target argument gives the name of the new window. If a window exists with that name already, it is reused. The replace attribute, if true, means that whatever page is currently open in that window will be removed from the window's session history. The features argument is ignored.
name
[ = value ]Returns the name of the window.
Can be set, to change the name.
close
()Closes the window.
stop
()Cancels the document load.
length
Returns the number of child browsing contexts.
Returns the indicated child browsing context.
Window
objectReturns the indicated element or collection of elements.
To allow Web pages to integrate with Web browsers, certain Web browser interface elements are exposed in a limited way to scripts in Web pages.
Each interface element is represented by a BarProp
object:
interface BarProp { attribute boolean visible; };
locationbar
. visible
Returns true if the location bar is visible; otherwise, returns false.
menubar
. visible
Returns true if the menu bar is visible; otherwise, returns false.
personalbar
. visible
Returns true if the personal bar is visible; otherwise, returns false.
scrollbars
. visible
Returns true if the scroll bars are visible; otherwise, returns false.
statusbar
. visible
Returns true if the status bar is visible; otherwise, returns false.
toolbar
. visible
Returns true if the toolbar is visible; otherwise, returns false.
The origin of a resource and the effective script origin of a resource are both either opaque identifiers or tuples consisting of a scheme component, a host component, a port component, and optionally extra data.
The extra data could include the certificate of the site when using encrypted connections, to ensure that if the site's secure certificate changes, the origin is considered to change as well.
domain
[ = domain ]Returns the current domain used for security checks.
Can be set to a value that removes subdomains, to change the effective script origin to allow pages on other subdomains of the same domain (if they do the same thing) to access each other.
The domain
attribute is used to enable pages on different hosts of a domain to access each others' DOMs.
Do not use the document.domain
attribute when using shared hosting. If an untrusted third party is able to host an HTTP server at the same IP address but on a different port, then the same-origin protection that normally protects two different sites on the same host will fail, as the ports are ignored when comparing origins after the document.domain
attribute has been used.
The sequence of Document
s in a browsing context is its session history.
History
objects provide a representation of the pages in the session history of browsing contexts. Each browsing context, including nested browsing contexts, has a distinct session history.
Each Document
object in a browsing context's session history is associated with a unique instance of the History
object, although they all must model the same underlying session history.
The history
attribute of the Window
interface must return the object implementing the History
interface for that Window
object's Document
.
History
objects represent their browsing context's session history as a flat list of session history entries. Each session history entry consists of either a URL or a state object, or both.
Titles associated with session history entries need not have any relation with the current title
of the Document
. The title of a session history entry is intended to explain the state of the document at that point, so that the user can navigate the document's history.
URLs without associated state objects are added to the session history as the user (or script) navigates from page to page.
A state object is an object representing a user interface state.
Pages can add state objects between their entry in the session history and the next ("forward") entry. These are then returned to the script when the user (or script) goes back in the history, thus enabling authors to use the "navigation" metaphor even in one-page applications.
State objects are intended to be used for two main purposes: first, storing a preparsed description of the state in the URL so that in the simple case an author doesn't have to do the parsing (though one would still need the parsing for handling URLs passed around by users, so it's only a minor optimization), and second, so that the author can store state that one wouldn't store in the URL because it only applies to the current Document
instance and it would have to be reconstructed if a new Document
were opened.
An example of the latter would be something like keeping track of the precise coordinate from which a popup div
was made to animate, so that if the user goes back, it can be made to animate to the same location. Or alternatively, it could be used to keep a pointer into a cache of data that would be fetched from the server based on the information in the URL, so that when going back and forward, the information doesn't have to be fetched again.
At any point, one of the entries in the session history is the current entry. This is the entry representing the active document of the browsing context. The current entry is usually an entry for the location of the Document
. However, it can also be one of the entries for state objects added to the history by that document.
An entry with persisted user state is one that also has user-agent defined state. This specification does not specify what kind of state can be stored.
For example, some user agents might want to persist the scroll position, or the values of form controls.
Entries that consist of state objects share the same Document
as the entry for the page that was active when they were added.
Contiguous entries that differ just by fragment identifier also share the same Document
.
All entries that share the same Document
(and that are therefore merely different states of one particular document) are contiguous by definition.
History
interfaceinterface History { readonly attribute long length; readonly attribute any state; void go(in optional long delta); void back(); void forward(); void pushState(in any data, in DOMString title, in optional DOMString url); void replaceState(in any data, in DOMString title, in optional DOMString url); };
history
. length
Returns the number of entries in the joint session history.
history
. state
Returns the current state object.
history
. go
( [ delta ] )Goes back or forward the specified number of steps in the joint session history.
A zero delta will reload the current page.
If the delta is out of range, does nothing.
history
. back
()Goes back one step in the joint session history.
If there is no previous page, does nothing.
history
. forward
()Goes forward one step in the joint session history.
If there is no next page, does nothing.
history
. pushState
(data, title [, url ] )Pushes the given data onto the session history, with the given title, and, if provided, the given URL.
history
. replaceState
(data, title [, url ] )Updates the current entry in the session history to have the given data, title, and, if provided, URL.
The joint session history of a History
object is the union of all the session histories of all browsing contexts of all the fully active Document
objects that share the History
object's top-level browsing context, with all the entries that are current entries in their respective session histories removed except
for the current entry of the joint session history.
The current entry of the joint session history is the entry that most recently became a current entry in its session history.
Entries in the joint session history are ordered chronologically by the time they were added to their respective session histories. (Since all these browsing contexts by definition share an event loop, there is always a well-defined sequential order in which their session histories had their entries added.) Each entry has an index; the earliest entry has index 0, and the subsequent entries are numbered with consecutively increasing integers (1, 2, 3, etc).
Consider a game where the user can navigate along a line, such that the user is always at some coordinate, and such that the user can bookmark the page corresponding to a particular coordinate, to return to it later.
A static page implementing the x=5 position in such a game could look like the following:
<!DOCTYPE HTML> <!-- this is http://example.com/line?x=5 --> <title>Line Game - 5</title> <p>You are at coordinate 5 on the line.</p> <p> <a href="?x=6">Advance to 6</a> or <a href="?x=4">retreat to 4</a>? </p>
The problem with such a system is that each time the user clicks, the whole page has to be reloaded. Here instead is another way of doing it, using script:
<!DOCTYPE HTML> <!-- this starts off as http://example.com/line?x=5 --> <title>Line Game - 5</title> <p>You are at coordinate <span id="coord">5</span> on the line.</p> <p> <a href="?x=6" onclick="go(1); return false;">Advance to 6</a> or <a href="?x=4" onclick="go(-1); return false;">retreat to 4</a>? </p> <script> var currentPage = 5; // prefilled by server function go(d) { setupPage(currentPage + d); history.pushState(currentPage, document.title, '?x=' + currentPage); } onpopstate = function(event) { setupPage(event.state); } function setupPage(page) { currentPage = page; document.title = 'Line Game - ' + currentPage; document.getElementById('coord').textContent = currentPage; document.links[0].href = '?x=' + (currentPage+1); document.links[0].textContent = 'Advance to ' + (currentPage+1); document.links[1].href = '?x=' + (currentPage-1); document.links[1].textContent = 'retreat to ' + (currentPage-1); } </script>
In systems without script, this still works like the previous example. However, users that do have script support can now navigate much faster, since there is no network access for the same experience. Furthermore, contrary to the experience the user would have with just a naïve script-based approach, bookmarking and navigating the session history still work.
In the example above, the data argument to the pushState()
method is the same information as would be sent to the server, but in a more convenient form, so that the script doesn't have to parse the URL each time the user navigates.
Applications might not use the same title for a session history entry as the value of the document's title
element at that time. For example, here is a simple page that shows a block in the title
element. Clearly, when navigating backwards to a previous state the user does not go back in time, and therefore it would be inappropriate to put the time in the session history title.
<!DOCTYPE HTML> <TITLE>Line</TITLE> <SCRIPT> setInterval(function () { document.title = 'Line - ' + new Date(); }, 1000); var i = 1; function inc() { set(i+1); history.pushState(i, 'Line - ' + i); } function set(newI) { i = newI; document.forms.F.I.value = newI; } </SCRIPT> <BODY ONPOPSTATE="set(event.state)"> <FORM NAME=F> State: <OUTPUT NAME=I>1</OUTPUT> <INPUT VALUE="Increment" TYPE=BUTTON ONCLICK="inc()"> </FORM>
Location
interfaceEach Document
object in a browsing context's session history is associated with a unique instance of a Location
object.
location
[ = value ]location
[ = value ]Returns a Location
object with the current page's location.
Can be set, to navigate to another page.
Location
objects provide a representation of their document's current address, and allow the current entry of the browsing context's session history to be changed, by adding or replacing entries in the history
object.
interface Location { stringifier attribute DOMString href; void assign(in DOMString url); void replace(in DOMString url); void reload(); // URL decomposition IDL attributes attribute DOMString protocol; attribute DOMString host; attribute DOMString hostname; attribute DOMString port; attribute DOMString pathname; attribute DOMString search; attribute DOMString hash; // resolving relative URLs DOMString resolveURL(in DOMString url); };
href
[ = value ]Returns the current page's location.
Can be set, to navigate to another page.
assign
(url)Navigates to the given page.
replace
(url)Removes the current page from the session history and navigates to the given page.
reload
()Reloads the current page.
resolveURL
(url)Resolves the given relative URL to an absolute URL.
The Location
interface also has the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, search
, and hash
.
The popstate
event is fired in certain cases when navigating to a session history entry.
interface PopStateEvent : Event { readonly attribute any state; void initPopStateEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean cancelableArg, in any stateArg); };
state
Returns a copy of the information that was provided to pushState()
or replaceState()
.
The initPopStateEvent()
method must initialize the event in a manner analogous to the similarly-named method in the DOM Events interfaces. [DOMEVENTS]
The hashchange
event is fired when navigating to a session history entry whose URL differs from that of the previous one only in the fragment identifier.
interface HashChangeEvent : Event { readonly attribute DOMString oldURL; readonly attribute DOMString newURL; void initHashChangeEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean cancelableArg, in DOMString oldURLArg, in DOMString newURLArg); };
oldURL
Returns the URL of the session history entry that was previously current.
newURL
Returns the URL of the session history entry that is now current.
The initHashChangeEvent()
method must initialize the event in a manner analogous to the similarly-named method in the DOM Events interfaces. [DOMEVENTS]
The pageshow
event is fired when traversing to a session history entry.
The pagehide
event is fired when traversing from a session history entry.
interface PageTransitionEvent : Event { readonly attribute boolean persisted; void initPageTransitionEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean cancelableArg, in boolean persistedArg); };
persisted
Returns false if the page is newly being loaded (and the load
event will fire). Otherwise, returns true.
The initPageTransitionEvent()
method must initialize the event in a manner analogous to the similarly-named method in the DOM Events interfaces. [DOMEVENTS]
interface BeforeUnloadEvent : Event { attribute DOMString returnValue; };
returnValue
[ = value ]Returns the current return value of the event (the message to show the user).
Can be set, to update the message.
There are no BeforeUnloadEvent
-specific initialization methods.
In order to enable users to continue interacting with Web applications and documents even when their network connection is unavailable — for instance, because they are traveling outside of their ISP's coverage area — authors can provide a manifest which lists the files that are needed for the Web application to work offline and which causes the user's browser to keep a copy of the files for use offline.
To illustrate this, consider a simple clock applet consisting of an HTML page "clock.html
", a CSS style sheet "clock.css
", and a JavaScript script "clock.js
".
Before adding the manifest, these three files might look like this:
<!-- clock.html --> <!DOCTYPE HTML> <html> <head> <title>Clock</title> <script src="clock.js"></script> <link rel="stylesheet" href="clock.css"> </head> <body> <p>The time is: <output id="clock"></output></p> </body> </html>
/* clock.css */ output { font: 2em sans-serif; }
/* clock.js */ setTimeout(function () { document.getElementById('clock').value = new Date(); }, 1000);
If the user tries to open the "clock.html
" page while offline, though, the user agent (unless it happens to have it still in the local cache) will fail with an error.
The author can instead provide a manifest of the three files:
CACHE MANIFEST clock.html clock.css clock.js
With a small change to the HTML file, the manifest (served as text/cache-manifest
) is linked to the application:
<!-- clock.html --> <!DOCTYPE HTML> <html manifest="clock.appcache"> <head> <title>Clock</title> <script src="clock.js"></script> <link rel="stylesheet" href="clock.css"> </head> <body> <p>The time is: <output id="clock"></output></p> </body> </html>
Now, if the user goes to the page, the browser will cache the files and make them available even when the user is offline.
Authors are encouraged to include the main page in the manifest also, but in practice the page that referenced the manifest is automatically cached even if it isn't explicitly mentioned.
HTTP cache headers and restrictions on caching pages served over TLS (encrypted, using https:
) are overridden by manifests. Thus, pages will not expire from an application cache before the user agent has updated it, and even applications served over TLS can be made to work offline.
When the user visits a page that declares a manifest, the browser will try to update the cache. It does this by fetching a copy of the manifest and, if the manifest has changed since the user agent last saw it, redownloading all the resources it mentions and caching them anew.
As this is going on, a number of events get fired on the ApplicationCache
object to keep the script updated as to the state of the cache update, so that the user can be notified appropriately. The events are as follows:
Event name | Interface | Dispatched when... | Next events |
---|---|---|---|
checking |
Event |
The user agent is checking for an update, or attempting to download the manifest for the first time. This is always the first event in the sequence. | noupdate , downloading , obsolete , error |
noupdate |
Event |
The manifest hadn't changed. | Last event in sequence. |
downloading |
Event |
The user agent has found an update and is fetching it, or is downloading the resources listed by the manifest for the first time. | progress , error , cached , updateready |
progress |
ProgressEvent |
The user agent is downloading resources listed by the manifest. | progress , error , cached , updateready |
cached |
Event |
The resources listed in the manifest have been downloaded, and the application is now cached. | Last event in sequence. |
updateready |
Event |
The resources listed in the manifest have been newly redownloaded, and the script can use swapCache() to switch to the new cache. |
Last event in sequence. |
obsolete |
Event |
The manifest was found to have become a 404 or 410 page, so the application cache is being deleted. | Last event in sequence. |
error |
Event |
The manifest was a 404 or 410 page, so the attempt to cache the application has been aborted. | Last event in sequence. |
The manifest hadn't changed, but the page referencing the manifest failed to download properly. | |||
A fatal error occurred while fetching the resources listed in the manifest. | |||
The manifest changed while the update was being run. | The user agent will try fetching the files again momentarily. |
This example manifest requires two images and a style sheet to be cached and whitelists a CGI script.
CACHE MANIFEST # the above line is required # this is a comment # there can be as many of these anywhere in the file # they are all ignored # comments can have spaces before them # but must be alone on the line # blank lines are ignored too # these are files that need to be cached they can either be listed # first, or a "CACHE:" header could be put before them, as is done # lower down. images/sound-icon.png images/background.png # note that each file has to be put on its own line # here is a file for the online whitelist -- it isn't cached, and # references to this file will bypass the cache, always hitting the # network (or trying to, if the user is offline). NETWORK: comm.cgi # here is another set of files to cache, this time just the CSS file. CACHE: style/default.css
It could equally well be written as follows:
CACHE MANIFEST NETWORK: comm.cgi CACHE: style/default.css images/sound-icon.png images/background.png
Offline application cache manifests can use absolute paths or even absolute URLs:
CACHE MANIFEST /main/home /main/app.js /settings/home /settings/app.js http://img.example.com/logo.png http://img.example.com/check.png http://img.example.com/cross.png
The following manifest defines a catch-all error page that is displayed for any page on the site while the user is offline. It also specifies that the online whitelist wildcard flag is open, meaning that accesses to resources on other sites will not be blocked. (Resources on the same site are already not blocked because of the catch-all fallback namespace.)
So long as all pages on the site reference this manifest, they will get cached locally as they are fetched, so that subsequent hits to the same page will load the page immediately from the cache. Until the manifest is changed, those pages will not be fetched from the server again. When the manifest changes, then all the files will be redownloaded.
Subresources, such as style sheets, images, etc, would only be cached using the regular HTTP caching semantics, however.
CACHE MANIFEST FALLBACK: / /offline.html NETWORK: *
Manifests must be served using the text/cache-manifest
MIME type. All resources served using the text/cache-manifest
MIME type must follow the syntax of application cache manifests, as described in this section.
An application cache manifest is a text file, whose text is encoded using UTF-8. Data in application cache manifests is line-based. Newlines must be represented by U+000A LINE FEED (LF) characters, U+000D CARRIAGE RETURN (CR) characters, or U+000D CARRIAGE RETURN (CR) U+000A LINE FEED (LF) pairs. [RFC3629]
This is a willful violation of RFC 2046, which requires all text/*
types to only allow CRLF line breaks. This requirement, however, is outdated; the use of CR, LF, and CRLF line breaks is commonly supported and indeed sometimes CRLF is not supported by text editors. [RFC2046]
The first line of an application cache manifest must consist of the string "CACHE", a single U+0020 SPACE character, the string "MANIFEST", and either a U+0020 SPACE character, a U+0009 CHARACTER TABULATION (tab) character, a U+000A LINE FEED (LF) character, or a U+000D CARRIAGE RETURN (CR) character. The first line may optionally be preceded by a U+FEFF BYTE ORDER MARK (BOM) character. If any other text is found on the first line, it is ignored.
Subsequent lines, if any, must all be one of the following:
Blank lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters only.
Comment lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters, followed by a single U+0023 NUMBER SIGN character (#), followed by zero or more characters other than U+000A LINE FEED (LF) and U+000D CARRIAGE RETURN (CR) characters.
Comments must be on a line on their own. If they were to be included on a line with a URL, the "#" would be mistaken for part of a fragment identifier.
Section headers change the current section. There are three possible section headers:
CACHE:
FALLBACK:
NETWORK:
Section header lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters, followed by one of the names above (including the U+003A COLON character (:)) followed by zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters.
Ironically, by default, the current section is the explicit section.
The format that data lines must take depends on the current section.
When the current section is the explicit section, data lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters, a valid URL identifying a resource other than the manifest itself, and then zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters.
When the current section is the fallback section, data lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters, a valid URL identifying a resource other than the manifest itself, one or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters, another valid URL identifying a resource other than the manifest itself, and then zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters.
When the current section is the online whitelist section, data lines must consist of zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters, either a single U+002A ASTERISK character (*) or a valid URL identifying a resource other than the manifest itself, and then zero or more U+0020 SPACE and U+0009 CHARACTER TABULATION (tab) characters.
Manifests may contain sections more than once. Sections may be empty.
If the manifest's <scheme> is https:
or another scheme intended for encrypted data transfer, then all URLs in explicit sections must have the same origin as the manifest itself.
URLs that are to be fallback pages associated with fallback namespaces, and those namespaces themselves, must be given in fallback sections, with the namespace being the first URL of the data line, and the corresponding fallback page being the second URL. All the other pages to be cached must be listed in explicit sections.
Fallback namespaces and fallback entries must have the same origin as the manifest itself.
A fallback namespace must not be listed more than once.
Namespaces that the user agent is to put into the online whitelist must all be specified in online whitelist sections. (This is needed for any URL that the page is intending to use to communicate back to the server.) To specify that all URLs are automatically whitelisted in this way, a U+002A ASTERISK character (*) may be specified as one of the URLs.
Authors should not include namespaces in the online whitelist for which another namespace in the online whitelist is a prefix match.
Relative URLs must be given relative to the manifest's own URL. All URLs in the manifest must have the same <scheme> as the manifest itself (either explicitly or implicitly, through the use of relative URLs).
URLs in manifests must not have fragment identifiers (i.e. the U+0023 NUMBER SIGN character isn't allowed in URLs in manifests).
Fallback namespaces and namespaces in the online whitelist are matched by prefix match.
interface ApplicationCache { // update status const unsigned short UNCACHED = 0; const unsigned short IDLE = 1; const unsigned short CHECKING = 2; const unsigned short DOWNLOADING = 3; const unsigned short UPDATEREADY = 4; const unsigned short OBSOLETE = 5; readonly attribute unsigned short status; // updates void update(); void swapCache(); // events attribute Function ; attribute Function onerror; attribute Function ; attribute Function ; attribute Function onprogress; attribute Function ; attribute Function ; attribute Function ; }; ApplicationCache implements EventTarget;
applicationCache
(In a window.) Returns the ApplicationCache
object that applies to the active document of that Window
.
applicationCache
(In a shared worker.) Returns the ApplicationCache
object that applies to the current shared worker. [WEBWORKERS]
status
Returns the current status of the application cache, as given by the constants defined below.
update
()Invokes the application cache download process.
Throws an INVALID_STATE_ERR
exception if there is no application cache to update.
swapCache
()Switches to the most recent application cache, if there is a newer one. If there isn't, throws an INVALID_STATE_ERR
exception.
This does not cause previously-loaded resources to be reloaded; for example, images do not suddenly get reloaded and style sheets and scripts do not get reparsed or reevaluated. The only change is that subsequent requests for cached resources will obtain the newer copies.
UNCACHED
(numeric value 0)The ApplicationCache
object's cache host is not associated with an application cache at this time.
IDLE
(numeric value 1)The ApplicationCache
object's cache host is associated with an application cache whose application cache group's update status is idle, and that application cache is the newest cache in its application cache group, and the application cache group is not marked as obsolete.
CHECKING
(numeric value 2)The ApplicationCache
object's cache host is associated with an application cache whose application cache group's update status is checking.
DOWNLOADING
(numeric value 3)The ApplicationCache
object's cache host is associated with an application cache whose application cache group's update status is downloading.
UPDATEREADY
(numeric value 4)The ApplicationCache
object's cache host is associated with an application cache whose application cache group's update status is idle, and whose application cache group is not marked as obsolete, but that application cache is not the newest cache in its group.
OBSOLETE
(numeric value 5)The ApplicationCache
object's cache host is associated with an application cache whose application cache group is marked as obsolete.
[Supplemental, NoInterfaceObject] interface NavigatorOnLine { readonly attribute boolean onLine; };
navigator
. onLine
Returns false if the user agent is definitely offline (disconnected from the network). Returns true if the user agent might be online.
The events online
and offline
are fired when the value of this attribute changes.
This attribute is inherently unreliable. A computer can be connected to a network without having Internet access.
In this example, an indicator is updated as the browser goes online and offline.
<!DOCTYPE HTML> <html> <head> <title>Online status</title> <script> function updateIndicator() { document.getElementById('indicator').textContext = navigator.onLine ? 'online' : 'offline'; } </script> </head> <body onload="updateIndicator()" ononline="updateIndicator()" onoffline="updateIndicator()"> <p>The network is: <span id="indicator">(state unknown)</span> </body> </html>
Various mechanisms can cause author-provided executable code to run in the context of a document. These mechanisms include, but are probably not limited to:
script
elements.javascript:
URLs (e.g. the src
attribute of img
elements, or an @import
rule in a CSS style
element block).addEventListener()
, by explicit event handler content attributes, by event handler IDL attributes, or otherwise.Many objects can have event handlers specified. These act as bubbling event listeners for the object on which they are specified.
An event handler can either have the value null or be set to a Function
object.
Event handlers are exposed in one or two ways.
The first way, common to all event handlers, is as an event handler IDL attribute.
The second way is as an event handler content attribute. Event handlers on HTML elements and some of the event handlers on Window
objects are exposed in this way.
Event handler content attributes, when specified, must contain valid JavaScript code which, when parsed, would match the FunctionBody
production after automatic semicolon insertion. [ECMA262]
When an event handler content attribute is set on an element owned by a Document
that is not in a browsing context, the corresponding event handler is not changed.
Event handlers always fire before event listeners attached using addEventListener()
.
The Function
interface represents a function in the scripting language being used. It is represented in IDL as follows:
[Callback=FunctionOnly, NoInterfaceObject] interface Function { any call(in any... arguments); };
The call(...)
method is the object's callback.
In JavaScript, any Function
object implements this interface.
If the Function
object is a JavaScript Function
, then when it is invoked by the user agent, the user agent must set the thisArg (as defined by ECMAScript edition 5 section 10.4.3 Entering Function Code) to the event handler's object. [ECMA262]
For example, the following document fragment:
<body onload="alert(this)" onclick="alert(this)">
...leads to an alert saying "[object Window]
" when the document is loaded, and an alert saying "[object HTMLBodyElement]
" whenever the user clicks something in the page.
The return value of the function affects whether the event is canceled or not: if the return value is false, the event is canceled (except for mouseover
events, where the return value has to be true to cancel the event). With beforeunload
events, the value is instead used to determine the message to show the user.
The atob()
and btoa()
methods allow authors to transform content to and from the base64 encoding.
[Supplemental, NoInterfaceObject] interface WindowBase64 { DOMString btoa(in DOMString btoa); DOMString atob(in DOMString atob); }; Window implements WindowBase64;
In these APIs, for mnemonic purposes, the "b" can be considered to stand for "binary", and the "a" for "ASCII". In practice, though, for primarily historical reasons, both the input and output of these functions are Unicode strings.
btoa
( data )Takes the input data, in the form of a Unicode string containing only characters in the range U+0000 to U+00FF, each representing a binary byte with values 0x00 to 0xFF respectively, and converts it to its base64 representation, which it returns.
Throws an INVALID_CHARACTER_ERR
exception if the input string contains any out-of-range characters.
atob
( data )Takes the input data, in the form of a Unicode string containing base64-encoded binary data, decodes it, and returns a string consisting of characters in the range U+0000 to U+00FF, each representing a binary byte with values 0x00 to 0xFF respectively, corresponding to that binary data.
Throws an INVALID_CHARACTER_ERR
exception if the input string is not valid base64 data.
Some base64 encoders add newlines or other whitespace to their output. The atob()
method throws an exception if its input contains characters other than those described by the regular expression bracket expression [+/=0-9A-Za-z]
, so other characters need to be removed before atob()
is used for decoding.
The setTimeout()
and setInterval()
methods allow authors to schedule timer-based callbacks.
[Supplemental, NoInterfaceObject] interface WindowTimers { long setTimeout(in any handler, in optional any timeout, in any... args); void clearTimeout(in long handle); long setInterval(in any handler, in optional any timeout, in any... args); void clearInterval(in long handle); }; Window implements WindowTimers;
setTimeout
( handler [, timeout [, arguments ] ] )Schedules a timeout to run handler after timeout milliseconds. Any arguments are passed straight through to the handler.
setTimeout
( code [, timeout ] )Schedules a timeout to compile and run code after timeout milliseconds.
clearTimeout
( handle )Cancels the timeout set with setTimeout()
identified by handle.
setInterval
( handler [, timeout [, arguments ] ] )Schedules a timeout to run handler every timeout milliseconds. Any arguments are passed straight through to the handler.
setInterval
( code [, timeout ] )Schedules a timeout to compile and run code every timeout milliseconds.
clearInterval
( handle )Cancels the timeout set with setInterval()
identified by handle.
This API does not guarantee that timers will fire exactly on schedule. Delays due to CPU load, other tasks, etc, are to be expected.
alert
(message)Displays a modal alert with the given message, and waits for the user to dismiss it.
A call to the navigator.yieldForStorageUpdates()
method is implied when this method is invoked.
confirm
(message)Displays a modal OK/Cancel prompt with the given message, waits for the user to dismiss it, and returns true if the user clicks OK and false if the user clicks Cancel.
A call to the navigator.yieldForStorageUpdates()
method is implied when this method is invoked.
prompt
(message [, default] )Displays a modal text field prompt with the given message, waits for the user to dismiss it, and returns the value that the user entered. If the user cancels the prompt, then returns null instead. If the second argument is present, then the given value is used as a default.
A call to the navigator.yieldForStorageUpdates()
method is implied when this method is invoked.
print
()Prompts the user to print the page.
A call to the navigator.yieldForStorageUpdates()
method is implied when this method is invoked.
showModalDialog
(url [, argument] )Prompts the user with the given page, waits for that page to close, and returns the return value.
A call to the navigator.yieldForStorageUpdates()
method is implied when this method is invoked.
[NoInterfaceObject] interface WindowModal { readonly attribute any dialogArguments; attribute DOMString returnValue; };
dialogArguments
Returns the argument argument that was passed to the showModalDialog()
method.
returnValue
[ = value ]Returns the current return value for the window.
Can be set, to change the value that will be returned by the showModalDialog()
method.
The window.close()
method can be used to close the browsing context.
Navigator
objectinterface Navigator { // objects implementing this interface also implement the interfaces given below }; Navigator implements NavigatorID; Navigator implements NavigatorOnLine; Navigator implements NavigatorContentUtils; Navigator implements NavigatorStorageUtils;
[Supplemental, NoInterfaceObject] interface NavigatorID { readonly attribute DOMString appName; readonly attribute DOMString appVersion; readonly attribute DOMString platform; readonly attribute DOMString userAgent; };
In certain cases, despite the best efforts of the entire industry, Web browsers have bugs and limitations that Web authors are forced to work around.
This section defines a collection of attributes that can be used to determine, from script, the kind of user agent in use, in order to work around these issues.
Client detection should always be limited to detecting known current versions; future versions and unknown versions should always be assumed to be fully compliant.
navigator
. appName
Returns the name of the browser.
navigator
. appVersion
Returns the version of the browser.
navigator
. platform
Returns the name of the platform.
navigator
. userAgent
Returns the complete User-Agent header.
[Supplemental, NoInterfaceObject] interface NavigatorContentUtils { // content handler registration void registerProtocolHandler(in DOMString scheme, in DOMString url, in DOMString title); void registerContentHandler(in DOMString mimeType, in DOMString url, in DOMString title); };
The registerProtocolHandler()
method allows Web sites to register themselves as possible handlers for particular schemes. For example, an online telephone messaging service could register itself as a handler of the sms:
scheme ([RFC5724]), so that if the user clicks on such a link, he is given the opportunity to use that Web site. Analogously, the registerContentHandler()
method allows Web sites to register themselves as possible handlers for content in a particular MIME type. For example, the same online telephone messaging service could register itself as a handler for text/directory
files ([RFC2425]), so that if the user has no
native application capable of handling vCards ([RFC2426]), his Web browser can instead suggest he use that site to view contact information stored on vCards that he opens.
navigator
. registerProtocolHandler
(scheme, url, title)navigator
. registerContentHandler
(mimeType, url, title)Registers a handler for the given scheme or content type, at the given URL, with the given title.
The string "%s
" in the URL is used as a placeholder for where to put the URL of the content to be handled.
Throws a SECURITY_ERR
exception if the user agent blocks the registration (this might happen if trying to register as a handler for "http", for instance).
Throws a SYNTAX_ERR
if the "%s
" string is missing in the URL.
[Supplemental, NoInterfaceObject] interface NavigatorStorageUtils { void yieldForStorageUpdates(); };
navigator
. yieldForStorageUpdates
()If a script uses the document.cookie
API, or the localStorage
API, the browser will block other scripts from accessing cookies or storage until the first script finishes. [WEBSTORAGE]
Calling the navigator.yieldForStorageUpdates()
method tells the user agent to unblock any other scripts that may be blocked, even though the script hasn't returned.
Values of cookies and items in the Storage
objects of localStorage
attributes can change after calling this method, whence its name. [WEBSTORAGE]
hidden
attributeAll HTML elements may have the content attribute set. The
attribute is a boolean attribute. When specified on an element, it indicates that the element is not yet, or is no longer, relevant.
In the following skeletal example, the attribute is used to hide the Web game's main screen until the user logs in:
<h1>The Example Game</h1> <section id="login"> <h2>Login</h2> <form> ... <!-- calls login() once the user's credentials have been checked --> </form> <script> function login() { // switch screens document.getElementById('login').hidden = true; document.getElementById('game').hidden = false; } </script> </section> <section id="game" hidden> ... </section>
The attribute must not be used to hide content that could legitimately be shown in another presentation. For example, it is incorrect to use
to hide panels in a tabbed dialog, because the tabbed interface is merely a kind of overflow presentation — one could equally well just show all the form controls in one big page with a scrollbar. It is similarly incorrect to use this attribute to hide content just from one presentation — if something is marked
, it is hidden from all presentations, including, for instance, screen readers.
Elements that are not should not link to or refer to elements that are
.
For example, it would be incorrect to use the href
attribute to link to a section marked with the attribute. If the content is not applicable or relevant, then there is no reason to link to it.
It would similarly be incorrect to use the ARIA aria-describedby
attribute to refer to descriptions that are themselves . Hiding a section means that it is not applicable or relevant to anyone at the current time, so clearly it cannot be a valid description of content the user can interact with.
Elements in a section hidden by the attribute are still active, e.g. scripts and form controls in such sections still execute and submit respectively. Only their presentation to the user changes.
The hidden
IDL attribute must reflect the content attribute of the same name.
click
()Acts as if the element was clicked.
tabindex
attributeThe tabindex
content attribute specifies whether the element is focusable, whether it can be reached using sequential focus navigation, and the relative order of the element for the purposes of sequential focus navigation. The name "tab index" comes from the common use of the "tab" key to navigate through the focusable elements. The term "tabbing" refers to moving forward through the focusable elements that can be reached using sequential focus navigation.
The tabindex
attribute, if specified, must have a value that is a valid integer.
The tabIndex
IDL attribute must reflect the value of the tabindex
content attribute. Its default value is 0 for elements that are focusable and −1 for elements that are not focusable.
activeElement
Returns the currently focused element.
hasFocus
()Returns true if the document has focus; otherwise, returns false.
focus
()Focuses the window. Use of this method is discouraged. Allow the user to control window focus instead.
blur
()Unfocuses the window. Use of this method is discouraged. Allow the user to control window focus instead.
focus
()Focuses the element.
blur
()Unfocuses the element. Use of this method is discouraged. Focus another element instead.
Do not use this method to hide the focus ring if you find the focus ring unsightly. Instead, use a CSS rule to override the 'outline' property.
For example, to hide the outline from links, you could use:
:link:focus, :visited:focus { outline: none; }
Each element that can be activated or focused can be assigned a single key combination to activate it, using the accesskey
attribute.
The exact shortcut is determined by the user agent, based on information about the user's keyboard, what keyboard shortcuts already exist on the platform, and what other shortcuts have been specified on the page, using the information provided in the accesskey
attribute as a guide.
In order to ensure that a relevant keyboard shortcut is available on a wide variety of input devices, the author can provide a number of alternatives in the accesskey
attribute.
Each alternative consists of a single character, such as a letter or digit.
User agents can provide users with a list of the keyboard shortcuts, but authors are encouraged to do so also. The accessKeyLabel
IDL attribute returns a string representing the actual key combination assigned by the user agent.
accesskey
attributeAll HTML elements may have the accesskey
content attribute set. The accesskey
attribute's value is used by the user agent as a guide for creating a keyboard shortcut that activates or focuses the element.
If specified, the value must be an ordered set of unique space-separated tokens that are case-sensitive, each of which must be exactly one Unicode code point in length.
In the following example, a variety of links are given with access keys so that keyboard users familiar with the site can more quickly navigate to the relevant pages:
<nav> <p> <a title="Consortium Activities" accesskey="A" href="/Consortium/activities">Activities</a> | <a title="Technical Reports and Recommendations" accesskey="T" href="/TR/">Technical Reports</a> | <a title="Alphabetical Site Index" accesskey="S" href="/Consortium/siteindex">Site Index</a> | <a title="About This Site" accesskey="B" href="/Consortium/">About Consortium</a> | <a title="Contact Consortium" accesskey="C" href="/Consortium/contact">Contact</a> </p> </nav>
In the following example, the search field is given two possible access keys, "s" and "0" (in that order). A user agent on a device with a full keyboard might pick Ctrl+Alt+S as the shortcut key, while a user agent on a small device with just a numeric keypad might pick just the plain unadorned key 0:
<form action="/search"> <label>Search: <input type="search" name="q" accesskey="s 0"></label> <input type="submit"> </form>
In the following example, a button has possible access keys described. A script then tries to update the button's label to advertise the key combination the user agent selected.
<input type=submit accesskey="N @ 1" value="Compose"> ... <script> function labelButton(button) { if (button.accessKeyLabel) button.value += ' (' + button.accessKeyLabel + ')'; } var inputs = document.getElementsByTagName('input'); for (var i = 0; i < inputs.length; i += 1) { if (inputs[i].type == "submit") labelButton(inputs[i]); } </script>
On one user agent, the button's label might become "Compose (⌘N)". On another, it might become "Compose (Alt+⇧+1)". If the user agent doesn't assign a key, it will be just "Compose". The exact string depends on what the assigned access key is, and on how the user agent represents that key combination.
The accessKey
IDL attribute must reflect the accesskey
content attribute.
contenteditable
attributeThe contenteditable
attribute is an enumerated attribute whose keywords are the empty string, true
, and false
. The empty string and the true
keyword map to the true state. The false
keyword maps to the false state. In addition, there is a third state, the inherit state, which is the missing value default (and the invalid value default).
The true state indicates that the element is editable. The inherit state indicates that the element is editable if its parent is. The false state indicates that the element is not editable.
contentEditable
[ = value ]Returns "true
", "false
", or "inherit
", based on the state of the contenteditable
attribute.
Can be set, to change that state.
Throws a SYNTAX_ERR
exception if the new value isn't one of those strings.
isContentEditable
Returns true if the element is editable; otherwise, returns false.
designMode
[ = value ]Returns "on
" if the document is editable, and "off
" if it isn't.
Can be set, to change the document's current state.
The spellcheck
attribute is an enumerated attribute whose keywords are the empty string, true
and false
. The empty string and the true
keyword map to the true state. The false
keyword maps to the false state. In addition, there is a third state, the default state, which is the missing value default (and the invalid value default).
The true state indicates that the element is to have its spelling and grammar checked. The default state indicates that the element is to act according to a default behavior, possibly based on the parent element's own spellcheck
state. The false state indicates that the element is not to be checked.
spellcheck
[ = value ]Returns true if the element is to have its spelling and grammar checked; otherwise, returns false.
Can be set, to override the default and set the spellcheck
content attribute.
This specification does not define the user interface for spelling and grammar checkers. A user agent could offer on-demand checking, could perform continuous checking while the checking is enabled, or could use other interfaces.
This section defines an event-based drag-and-drop mechanism.
This specification does not define exactly what a drag-and-drop operation actually is.
On a visual medium with a pointing device, a drag operation could be the default action of a mousedown
event that is followed by a series of mousemove
events, and the drop could be triggered by the mouse being released.
On media without a pointing device, the user would probably have to explicitly indicate his intention to perform a drag-and-drop operation, stating what he wishes to drag and where he wishes to drop it, respectively.
To make an element draggable is simple: give the element a draggable
attribute, and set an event listener for dragstart
that stores the data being dragged.
The event handler typically needs to check that it's not a text selection that is being dragged, and then needs to store data into the DataTransfer
object and set the allowed effects (copy, move, link, or some combination).
For example:
<p>What fruits do you like?</p> <ol ondragstart="dragStartHandler(event)"> <li draggable="true" data-value="fruit-apple">Apples</li> <li draggable="true" data-value="fruit-orange">Oranges</li> <li draggable="true" data-value="fruit-pear">Pears</li> </ol> <script> var internalDNDType = 'text/x-example'; // set this to something specific to your site function dragStartHandler(event) { if (event.target instanceof HTMLLIElement) { // use the element's data-value="" attribute as the value to be moving: event.dataTransfer.setData(internalDNDType, event.target.dataset.value); event.dataTransfer.effectAllowed = 'move'; // only allow moves } else { event.preventDefault(); // don't allow selection to be dragged } } </script>
To accept a drop, the drop target has to have a dropzone
attribute and listen to the drop
event.
The value of the dropzone
attribute specifies what kind of data to accept (e.g. "s:text/plain
" to accept any text strings, or "f:image/png
" to accept a PNG image file) and what kind of feedback to give (e.g. "move
" to indicate that the data will be moved).
Instead of using the dropzone
attribute, a drop target can handle the dragenter
event (to report whether or not the drop target is to accept the drop) and the dragover
event (to specify what feedback is to be shown to the user).
The drop
event allows the actual drop to be performed. This event needs to be canceled, so that the dropEffect
attribute's value can be used by the source (otherwise it's reset).
For example:
<p>Drop your favorite fruits below:</p> <ol dropzone="move s:text/x-example" ondrop="dropHandler(event)"> <-- don't forget to change the "text/x-example" type to something specific to your site --> </ol> <script> var internalDNDType = 'text/x-example'; // set this to something specific to your site function dropHandler(event) { var li = document.createElement('li'); var data = event.dataTransfer.getData(internalDNDType); if (data == 'fruit-apple') { li.textContent = 'Apples'; } else if (data == 'fruit-orange') { li.textContent = 'Oranges'; } else if (data == 'fruit-pear') { li.textContent = 'Pears'; } else { li.textContent = 'Unknown Fruit'; } event.target.appendChild(li); } </script>
To remove the original element (the one that was dragged) from the display, the dragend
event can be used.
For our example here, that means updating the original markup to handle that event:
<p>What fruits do you like?</p> <ol ondragstart="dragStartHandler(event)" ondragend="dragEndHandler(event)"> ...as before... </ol> <script> function dragStartHandler(event) { // ...as before... } function dragEndHandler(event) { // remove the dragged element event.target.parentNode.removeChild(event.target); } </script>
The data that underlies a drag-and-drop operation, known as the drag data store, consists of the following information:
A drag data store item list, which is a list of items representing the dragged data, each consisting of the following information:
The kind of data:
Text.
Binary data with a file name.
A Unicode string giving the type or format of the data, generally given by a MIME type. Some values that are not MIME types are special-cased for legacy reasons. The API does not enforce the use of MIME types; other values can be used as well. In all cases, however, the values are all converted to ASCII lowercase by the API.
Strings that contain space characters cannot be used with the dropzone
attribute, so authors are encouraged to use only MIME types or custom strings (without spaces).
There is a limit of one Plain Unicode string item per item type string.
A Unicode or binary string, in some cases with a file name (itself a Unicode string), as per the drag data item kind.
The drag data store item list is ordered in the order that the items were added to the list; most recently added last.
The following information, used to generate the UI feedback during the drag:
A drag data store mode, which is one of the following:
For the dragstart
event. New data can be added to the drag data store.
For the drop
event. The list of items representing dragged data can be read, including the data. No new data can be added.
For all other events. The formats and kinds in the drag data store list of items representing dragged data can be enumerated, but the data itself is unavailable and no new data can be added.
A drag data store allowed effects state, which is a string.
When a drag data store is created, it must be initialized such that its drag data store item list is empty, it has no drag data store default feedback, its drag data store elements list is empty, it has no drag data store bitmap / drag data store hot spot coordinate, its drag data store mode is protected mode,
and its drag data store allowed effects state is the string "uninitialized
".
DataTransfer
interfaceDataTransfer
objects are used to expose the drag data store that underlies a drag-and-drop operation.
interface DataTransfer { attribute DOMString dropEffect; attribute DOMString effectAllowed; readonly attribute DataTransferItems items; void setDragImage(in Element image, in long x, in long y); void addElement(in Element element); /* old interface */ readonly attribute DOMStringList types; DOMString getData(in DOMString format); void setData(in DOMString format, in DOMString data); void clearData(in optional DOMString format); readonly attribute FileList files; };
dropEffect
[ = value ]Returns the kind of operation that is currently selected. If the kind of operation isn't one of those that is allowed by the effectAllowed
attribute, then the operation will fail.
Can be set, to change the selected operation.
The possible values are "none
", "copy
", "link
", and "move
".
effectAllowed
[ = value ]Returns the kinds of operations that are to be allowed.
Can be set, to change the allowed operations.
The possible values are "none
", "copy
", "copyLink
", "copyMove
", "link
", "linkMove
", "move
", "all
", and "uninitialized
",
items
Returns a DataTransferItems
object, with the drag data.
setDragImage
(element, x, y)Uses the given element to update the drag feedback, replacing any previously specified feedback.
addElement
(element)Adds the given element to the list of elements used to render the drag feedback.
types
Returns a DOMStringList
listing the formats that were set in the dragstart
event. In addition, if any files are being dragged, then one of the types will be the string "Files
".
getData
(format)Returns the specified data. If there is no such data, returns the empty string.
setData
(format, data)Adds the specified data.
clearData
( [ format ] )Removes the data of the specified formats. Removes all data if the argument is omitted.
files
Returns a FileList
of the files being dragged, if any.
DataTransfer
objects are used during the drag-and-drop events, and are only valid while those events are being dispatched.
DataTransferItems
interfaceEach DataTransfer
object is associated with a DataTransferItems
object.
interface DataTransferItems { readonly attribute unsigned long length; getter DataTransferItem (in unsigned long index); deleter void (in unsigned long index); void clear(); DataTransferItem add(in DOMString data, in DOMString type); DataTransferItem add(in File data);};
length
Returns the number of items in the drag data store.
Returns the DataTransferItem
object representing the indexth entry in the drag data store.
delete
items[index]Removes the indexth entry in the drag data store.
clear
()Removes all the entries in the drag data store.
add
(data)add
(data, type)Adds a new entry for the given data to the drag data store. If the data is plain text then a type string has to be provided also.
DataTransferItem
interfaceEach DataTransferItem
object is associated with a DataTransfer
object.
interface DataTransferItem {
readonly attribute DOMString kind;
readonly attribute DOMString type;
void getAsString(in FunctionStringCallback callback); File getAsFile();};
[Callback=FunctionOnly, NoInterfaceObject]
interface FunctionStringCallback {
void handleEvent(in DOMString data);
};
kind
Returns the drag data item kind, one of: "string", "file".
type
Returns the drag data item type string.
getAsString
(callback)Invokes the callback with the string data as the argument, if the drag data item kind is Plain Unicode string.
getAsFile
()Returns a File
object, if the drag data item kind is File.
DragEvent
interfaceThe drag-and-drop processing model involves several events. They all use the DragEvent
interface.
interface DragEvent : MouseEvent { readonly attribute DataTransfer dataTransfer; void initDragEvent(in DOMString typeArg, in boolean canBubbleArg, in boolean cancelableArg, in any dummyArg, in long detailArg, in long screenXArg, in long screenYArg, in long clientXArg, in long clientYArg, in boolean ctrlKeyArg, in boolean altKeyArg, in boolean shiftKeyArg, in boolean metaKeyArg, in unsigned short buttonArg, in EventTarget relatedTargetArg, in DataTransfer dataTransferArg); };
dataTransfer
Returns the DataTransfer
object for the event.
The initDragEvent()
method must initialize the event in a manner analogous to the similarly-named method in the DOM Events interfaces, except that the dummyArg argument must be ignored. [DOMEVENTS]
The following events are involved in the drag-and-drop model.
Event Name | Target | Cancelable? | Drag data store mode | dropEffect |
Default Action |
---|---|---|---|---|---|
dragstart |
Source node | ✓ Cancelable | Read/write mode | "none " |
Initiate the drag-and-drop operation |
drag |
Source node | ✓ Cancelable | Protected mode | "none " |
Continue the drag-and-drop operation |
dragenter |
Immediate user selection or the body element | ✓ Cancelable | Protected mode | Based on effectAllowed value |
Reject immediate user selection as potential target element |
dragleave |
Previous target element | — | Protected mode | "none " |
None |
dragover |
Current target element | ✓ Cancelable | Protected mode | Based on effectAllowed value |
Reset the current drag operation to "none" |
drop |
Current target element | ✓ Cancelable | Read-only mode | Current drag operation | Varies |
dragend |
Source node | — | Protected mode | Current drag operation | Varies |
Not shown in the above table: all these events bubble, and the effectAllowed
attribute always has the value it had after the previous event was fired, defaulting to "uninitialized
" in the dragstart
event.
draggable
attributeAll HTML elements may have the draggable
content attribute set. The draggable
attribute is an enumerated attribute. It has three states. The first state is true and it has the keyword true
. The second state is false and it has the keyword false
. The third state is auto; it has no keywords but it is the missing value default.
The true state means the element is draggable; the false state means that it is not. The auto state uses the default behavior of the user agent.
draggable
[ = value ]Returns true if the element is draggable; otherwise, returns false.
Can be set, to override the default and set the draggable
content attribute.
dropzone
attributeAll HTML elements may have the dropzone
content attribute set. When specified, its value must be an unordered set of unique space-separated tokens that are ASCII case-insensitive. The allowed values are the following:
copy
Indicates that dropping an accepted item on the element will result in a copy of the dragged data.
move
Indicates that dropping an accepted item on the element will result in the dragged data being moved to the new location.
link
Indicates that dropping an accepted item on the element will result in a link to the original data.
s:
")Indicates that items with the drag data item kind Plain Unicode string and the drag data item type string set to a value that matches the remainder of the keyword are accepted.
f:
")Indicates that items with the drag data item kind File and the drag data item type string set to a value that matches the remainder of the keyword are accepted.
The dropzone
content attribute's values must not have more than one of the three feedback values (copy
, move
, and link
) specified. If none are specified, the copy
value is implied.
The dropzone
IDL attribute must reflect the content attribute of the same name.
In this example, a div
element is made into a drop target for image files using the dropzone
attribute. Images dropped into the target are then displayed.
<div dropzone="copy f:image/png f:image/gif f:image/jpeg" ondrop="receive(event, this)"> <p>Drop an image here to have it displayed.</p> </div> <script> function receive(event, element) { var data = event.dataTransfer.items; for (var i = 0; i < data.length; i += 1) { if ((data[i].kind == 'file') && (data[i].type.match('^image/'))) { var img = new Image(); img.src = window.createObjectURL(data[i].getAsFile()); element.appendChild(img); } } } </script>
execCommand
(commandId [, showUI [, value ] ] )Runs the action specified by the first argument, as described in the list below. The second and third arguments sometimes affect the action. (If they don't they are ignored.)
queryCommandEnabled
(commandId)Returns whether the given command is enabled, as described in the list below.
queryCommandIndeterm
(commandId)Returns whether the given command is indeterminate, as described in the list below.
queryCommandState
(commandId)Returns the state of the command, as described in the list below.
queryCommandSupported
(commandId)Returns true if the command is supported; otherwise, returns false.
queryCommandValue
(commandId)Returns the value of the command, as described in the list below.
A document is ready for editing host commands if it has a selection that is entirely within an editing host, or if it has no selection but its caret is inside an editing host.
The possible values for commandId, and their corresponding meanings, are as follows.
bold
b
element. False otherwise.true
" if the expression given for the "State" above is true, the string "false
" otherwise.createLink
false
".delete
false
".formatBlock
formatBlock
candidate, does nothing.false
".forwardDelete
false
".insertImage
false
".insertHTML
false
".insertLineBreak
false
".insertOrderedList
false
".insertUnorderedList
false
".insertParagraph
false
".insertText
false
".italic
i
element. False otherwise.true
" if the expression given for the "State" above is true, the string "false
" otherwise.redo
false
".selectAll
false
".subscript
sub
element. False otherwise.true
" if the expression given for the "State" above is true, the string "false
" otherwise.superscript
sup
element. False otherwise.true
" if the expression given for the "State" above is true, the string "false
" otherwise.undo
false
".unlink
a
element that has an href
attribute.false
".unselect
false
".This section only describes the rules for resources labeled with an HTML MIME type. Rules for XML resources are discussed in the section below entitled "The XHTML syntax".
Documents must consist of the following parts, in the given order:
html
element.The various types of content mentioned above are described in the next few sections.
In addition, there are some restrictions on how character encoding declarations are to be serialized, as discussed in the section on that topic.
Space characters before the root html
element, and space characters at the start of the html
element and before the head
element, will be dropped when the document is parsed; space characters after the root html
element will be parsed as if they were at the end of the body
element. Thus, space characters around the root element do not round-trip.
It is suggested that newlines be inserted after the DOCTYPE, after any comments that are before the root element, after the html
element's start tag (if it is not omitted), and after any comments that are inside the html
element but before the head
element.
Many strings in the HTML syntax (e.g. the names of elements and their attributes) are case-insensitive, but only for characters in the ranges U+0041 to U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) and U+0061 to U+007A (LATIN SMALL LETTER A to LATIN SMALL LETTER Z). For convenience, in this section this is just referred to as "case-insensitive".
A DOCTYPE is a required preamble.
DOCTYPEs are required for legacy reasons. When omitted, browsers tend to use a different rendering mode that is incompatible with some specifications. Including the DOCTYPE in a document ensures that the browser makes a best-effort attempt at following the relevant specifications.
A DOCTYPE must consist of the following components, in this order:
<!DOCTYPE
".html
".In other words, <!DOCTYPE html>
, case-insensitively.
For the purposes of HTML generators that cannot output HTML markup with the short DOCTYPE "<!DOCTYPE html>
", a DOCTYPE legacy string may be inserted into the DOCTYPE (in the position defined above). This string must consist of:
SYSTEM
".about:legacy-compat
".In other words, <!DOCTYPE html SYSTEM "about:legacy-compat">
or <!DOCTYPE html SYSTEM 'about:legacy-compat'>
, case-insensitively except for the part in single or double quotes.
The DOCTYPE legacy string should not be used unless the document is generated from a system that cannot output the shorter string.
To help authors transition from HTML4 and XHTML1, an obsolete permitted DOCTYPE string can be inserted into the DOCTYPE (in the position defined above). This string must consist of:
PUBLIC
".Public identifier | System identifier |
---|---|
-//W3C//DTD HTML 4.0//EN |
|
-//W3C//DTD HTML 4.0//EN |
http://www.w3.org/TR/REC-html40/strict.dtd |
-//W3C//DTD HTML 4.01//EN |
|
-//W3C//DTD HTML 4.01//EN |
http://www.w3.org/TR/html4/strict.dtd |
-//W3C//DTD XHTML 1.0 Strict//EN |
http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd |
-//W3C//DTD XHTML 1.1//EN |
http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd |
A DOCTYPE containing an obsolete permitted DOCTYPE string is an obsolete permitted DOCTYPE. Authors should not use obsolete permitted DOCTYPEs, as they are unnecessarily long.
There are five different kinds of elements: void elements, raw text elements, RCDATA elements, foreign elements, and normal elements.
area
, base
, br
, col
, command
, embed
, hr
, img
, input
, keygen
, link
, meta
, param
, source
, track
, wbr
script
, style
textarea
, title
Tags are used to delimit the start and end of elements in the markup. Raw text, RCDATA, and normal elements have a start tag to indicate where they begin, and an end tag to indicate where they end. The start and end tags of certain normal elements can be omitted, as described later. Those that cannot be omitted must not be omitted. Void elements only have a start tag; end tags must not be specified for void elements. Foreign elements must either have a start tag and an end tag, or a start tag that is marked as self-closing, in which case they must not have an end tag.
The contents of the element must be placed between just after the start tag (which might be implied, in certain cases) and just before the end tag (which again, might be implied in certain cases). The exact allowed contents of each individual element depend on the content model of that element, as described earlier in this specification. Elements must not contain content that their content model disallows. In addition to the restrictions placed on the contents by those content models, however, the five types of elements have additional syntactic requirements.
Void elements can't have any contents (since there's no end tag, no content can be put between the start tag and the end tag).
Raw text elements can have text, though it has restrictions described below.
RCDATA elements can have text and character references, but the text must not contain an ambiguous ampersand. There are also further restrictions described below.
Foreign elements whose start tag is marked as self-closing can't have any contents (since, again, as there's no end tag, no content can be put between the start tag and the end tag). Foreign elements whose start tag is not marked as self-closing can have text, character references, CDATA sections, other elements, and comments, but the text must not contain the character U+003C LESS-THAN SIGN (<) or an ambiguous ampersand.
The HTML syntax does not support namespace declarations, even in foreign elements.
For instance, consider the following HTML fragment:
<p> <svg> <metadata> <!-- this is invalid --> <cdr:license xmlns:cdr="http://www.example.com/cdr/metadata" name="MIT"/> </metadata> </svg> </p>
The innermost element, cdr:license
, is actually in the SVG namespace, as the "xmlns:cdr
" attribute has no effect (unlike in XML). In fact, as the comment in the fragment above says, the fragment is actually non-conforming. This is because the SVG specification does not define any elements called "cdr:license
" in the SVG namespace.
Normal elements can have text, character references, other elements, and comments, but the text must not contain the character U+003C LESS-THAN SIGN (<) or an ambiguous ampersand. Some normal elements also have yet more restrictions on what content they are allowed to hold, beyond the restrictions imposed by the content model and those described in this paragraph. Those restrictions are described below.
Tags contain a tag name, giving the element's name. HTML elements all have names that only use characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), U+0061 LATIN SMALL LETTER A to U+007A LATIN SMALL LETTER Z, and U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER Z. In the HTML syntax, tag names, even those for foreign elements, may be written with any mix of lower- and uppercase letters that, when converted to all-lowercase, matches the element's tag name; tag names are case-insensitive.
Start tags must have the following format:
End tags must have the following format:
Attributes for an element are expressed inside the element's start tag.
Attributes have a name and a value. Attribute names must consist of one or more characters other than the space characters, U+0000 NULL, U+0022 QUOTATION MARK ("), U+0027 APOSTROPHE ('), U+003E GREATER-THAN SIGN (>), U+002F SOLIDUS (/), and U+003D EQUALS SIGN (=) characters, the control characters, and any characters that are not defined by Unicode. In the HTML syntax, attribute names, even those for foreign elements, may be written with any mix of lower- and uppercase letters that are an ASCII case-insensitive match for the attribute's name.
Attribute values are a mixture of text and character references, except with the additional restriction that the text cannot contain an ambiguous ampersand.
Attributes can be specified in four different ways:
Just the attribute name. The value is implicitly the empty string.
In the following example, the disabled
attribute is given with the empty attribute syntax:
<input disabled>
If an attribute using the empty attribute syntax is to be followed by another attribute, then there must be a space character separating the two.
The attribute name, followed by zero or more space characters, followed by a single U+003D EQUALS SIGN character, followed by zero or more space characters, followed by the attribute value, which, in addition to the requirements given above for attribute values, must not contain any literal space characters, any U+0022 QUOTATION MARK characters ("), U+0027 APOSTROPHE characters ('), U+003D EQUALS SIGN characters (=), U+003C LESS-THAN SIGN characters (<), U+003E GREATER-THAN SIGN characters (>), or U+0060 GRAVE ACCENT characters (`), and must not be the empty string.
In the following example, the value
attribute is given with the unquoted attribute value syntax:
<input value=yes>
If an attribute using the unquoted attribute syntax is to be followed by another attribute or by the optional U+002F SOLIDUS character (/) allowed in step 6 of the start tag syntax above, then there must be a space character separating the two.
The attribute name, followed by zero or more space characters, followed by a single U+003D EQUALS SIGN character, followed by zero or more space characters, followed by a single U+0027 APOSTROPHE character ('), followed by the attribute value, which, in addition to the requirements given above for attribute values, must not contain any literal U+0027 APOSTROPHE characters ('), and finally followed by a second single U+0027 APOSTROPHE character (').
In the following example, the type
attribute is given with the single-quoted attribute value syntax:
<input type='checkbox'>
If an attribute using the single-quoted attribute syntax is to be followed by another attribute, then there must be a space character separating the two.
The attribute name, followed by zero or more space characters, followed by a single U+003D EQUALS SIGN character, followed by zero or more space characters, followed by a single U+0022 QUOTATION MARK character ("), followed by the attribute value, which, in addition to the requirements given above for attribute values, must not contain any literal U+0022 QUOTATION MARK characters ("), and finally followed by a second single U+0022 QUOTATION MARK character (").
In the following example, the name
attribute is given with the double-quoted attribute value syntax:
<input name="be evil">
If an attribute using the double-quoted attribute syntax is to be followed by another attribute, then there must be a space character separating the two.
There must never be two or more attributes on the same start tag whose names are an ASCII case-insensitive match for each other.
When a foreign element has one of the namespaced attributes given by the local name and namespace of the first and second cells of a row from the following table, it must be written using the name given by the third cell from the same row.
Local name | Namespace | Attribute name |
---|---|---|
actuate |
XLink namespace | xlink:actuate |
arcrole |
XLink namespace | xlink:arcrole |
href |
XLink namespace | xlink:href |
role |
XLink namespace | xlink:role |
show |
XLink namespace | xlink:show |
title |
XLink namespace | xlink:title |
type |
XLink namespace | xlink:type |
base |
XML namespace | xml:base |
lang |
XML namespace | xml:lang |
space |
XML namespace | xml:space |
xmlns |
XMLNS namespace | xmlns |
xlink |
XMLNS namespace | xmlns:xlink |
No other namespaced attribute can be expressed in the HTML syntax.
Certain tags can be omitted.
Omitting an element's start tag does not mean the element is not present; it is implied, but it is still there. An HTML document always has a root html
element, even if the string <html>
doesn't appear anywhere in the markup.
An html
element's start tag may be omitted if the first thing inside the html
element is not a comment.
An html
element's end tag may be omitted if the html
element is not immediately followed by a comment.
A head
element's start tag may be omitted if the element is empty, or if the first thing inside the head
element is an element.
A head
element's end tag may be omitted if the head
element is not immediately followed by a space character or a comment.
A body
element's start tag may be omitted if the element is empty, or if the first thing inside the body
element is not a space character or a comment, except if the first thing inside the body
element is a script
or style
element.
A body
element's end tag may be omitted if the body
element is not immediately followed by a comment.
A li
element's end tag may be omitted if the li
element is immediately followed by another li
element or if there is no more content in the parent element.
A dt
element's end tag may be omitted if the dt
element is immediately followed by another dt
element or a dd
element.
A dd
element's end tag may be omitted if the dd
element is immediately followed by another dd
element or a dt
element, or if there is no more content in the parent element.
A p
element's end tag may be omitted if the p
element is immediately followed by an address
, article
, aside
, blockquote
, dir
, div
, dl
, fieldset
, footer
, form
, h1
, h2
, h3
, h4
, h5
, h6
, header
, hgroup
, hr
, menu
, nav
, ol
, p
, pre
, section
, table
, or ul
, element, or if there is no more content in the parent element and the parent element is not an a
element.
An rt
element's end tag may be omitted if the rt
element is immediately followed by an rt
or rp
element, or if there is no more content in the parent element.
An rp
element's end tag may be omitted if the rp
element is immediately followed by an rt
or rp
element, or if there is no more content in the parent element.
An optgroup
element's end tag may be omitted if the optgroup
element is immediately followed by another optgroup
element, or if there is no more content in the parent element.
An option
element's end tag may be omitted if the option
element is immediately followed by another option
element, or if it is immediately followed by an optgroup
element, or if there is no more content in the parent element.
A colgroup
element's start tag may be omitted if the first thing inside the colgroup
element is a col
element, and if the element is not immediately preceded by another colgroup
element whose end tag has been omitted. (It can't be omitted if the element is empty.)
A colgroup
element's end tag may be omitted if the colgroup
element is not immediately followed by a space character or a comment.
A thead
element's end tag may be omitted if the thead
element is immediately followed by a tbody
or tfoot
element.
A tbody
element's start tag may be omitted if the first thing inside the tbody
element is a tr
element, and if the element is not immediately preceded by a tbody
, thead
, or tfoot
element whose end tag has been omitted. (It can't be omitted if the element is empty.)
A tbody
element's end tag may be omitted if the tbody
element is immediately followed by a tbody
or tfoot
element, or if there is no more content in the parent element.
A tfoot
element's end tag may be omitted if the tfoot
element is immediately followed by a tbody
element, or if there is no more content in the parent element.
A tr
element's end tag may be omitted if the tr
element is immediately followed by another tr
element, or if there is no more content in the parent element.
A td
element's end tag may be omitted if the td
element is immediately followed by a td
or th
element, or if there is no more content in the parent element.
A th
element's end tag may be omitted if the th
element is immediately followed by a td
or th
element, or if there is no more content in the parent element.
However, a start tag must never be omitted if it has any attributes.
For historical reasons, certain elements have extra restrictions beyond even the restrictions given by their content model.
A table
element must not contain tr
elements, even though these elements are technically allowed inside table
elements according to the content models described in this specification. (If a tr
element is put inside a table
in the markup, it will in fact imply a tbody
start tag before it.)
A single newline may be placed immediately after the start tag of pre
and textarea
elements. This does not affect the processing of the element. The otherwise optional newline must be included if the element's contents themselves start with a newline (because otherwise the leading newline in the contents would be treated like the optional newline, and ignored).
The text in raw text and RCDATA elements must not contain any occurrences of the string "</
" (U+003C LESS-THAN SIGN, U+002F SOLIDUS) followed by characters that case-insensitively match the tag name of the element followed by one of U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), U+000C FORM FEED (FF), U+000D CARRIAGE RETURN (CR), U+0020 SPACE, U+003E GREATER-THAN SIGN (>), or U+002F SOLIDUS (/).
Text is allowed inside elements, attribute values, and comments. Text must consist of Unicode characters. Text must not contain U+0000 characters. Text must not contain permanently undefined Unicode characters (noncharacters). Text must not contain control characters other than space characters. Extra constraints are placed on what is and what is not allowed in text based on where the text is to be put, as described in the other sections.
Newlines in HTML may be represented either as U+000D CARRIAGE RETURN (CR) characters, U+000A LINE FEED (LF) characters, or pairs of U+000D CARRIAGE RETURN (CR), U+000A LINE FEED (LF) characters in that order.
Where character references are allowed, a character reference of a U+000A LINE FEED (LF) character (but not a U+000D CARRIAGE RETURN (CR) character) also represents a newline.
In certain cases described in other sections, text may be mixed with character references. These can be used to escape characters that couldn't otherwise legally be included in text.
Character references must start with a U+0026 AMPERSAND character (&). Following this, there are three possible kinds of character references:
The numeric character reference forms described above are allowed to reference any Unicode code point other than U+0000, U+000D, permanently undefined Unicode characters (noncharacters), and control characters other than space characters.
An ambiguous ampersand is a U+0026 AMPERSAND character (&) that is followed by one or more characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), U+0061 LATIN SMALL LETTER A to U+007A LATIN SMALL LETTER Z, and U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER Z, followed by a U+003B SEMICOLON character (;), where these characters do not match any of the names given in the named character references section.
CDATA sections must consist of the following components, in this order:
<![CDATA[
".]]>
".]]>
".CDATA sections can only be used in foreign content (MathML or SVG). In this example, a CDATA section is used to escape the contents of an ms
element:
<p>You can add a string to a number, but this stringifies the number:</p> <math> <ms><![CDATA[x<y]]></ms> <mo>+</mo> <mn>3</mn> <mo>=</mo> <ms><![CDATA[x<y3]]></ms> </math>
Comments must start with the four character sequence U+003C LESS-THAN SIGN, U+0021 EXCLAMATION MARK, U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS (<!--
). Following this sequence, the comment may have text, with the additional restriction that the text must not start with a single U+003E GREATER-THAN SIGN character (>), nor start with a U+002D HYPHEN-MINUS character (-) followed by a U+003E GREATER-THAN SIGN (>) character, nor contain two consecutive U+002D HYPHEN-MINUS characters (--
), nor end with a U+002D HYPHEN-MINUS character (-). Finally, the comment must be ended by the three character sequence U+002D HYPHEN-MINUS, U+002D HYPHEN-MINUS, U+003E GREATER-THAN SIGN (-->
).
This table lists the character reference names that are supported by HTML, and the code points to which they refer. It is referenced by the previous sections.
Name | Character(s) | Glyph |
---|---|---|
AElig; |
U+000C6 | Æ |
AMP; |
U+00026 | & |
Aacute; |
U+000C1 | Á |
Abreve; |
U+00102 | Ă |
Acirc; |
U+000C2 | Â |
Acy; |
U+00410 | А |
Afr; |
U+1D504 | 𝔄 |
Agrave; |
U+000C0 | À |
Alpha; |
U+00391 | Α |
Amacr; |
U+00100 | Ā |
And; |
U+02A53 | ⩓ |
Aogon; |
U+00104 | Ą |
Aopf; |
U+1D538 | 𝔸 |
ApplyFunction; |
U+02061 | |
Aring; |
U+000C5 | Å |
Ascr; |
U+1D49C | 𝒜 |
Assign; |
U+02254 | ≔ |
Atilde; |
U+000C3 | Ã |
Auml; |
U+000C4 | Ä |
Backslash; |
U+02216 | ∖ |
Barv; |
U+02AE7 | ⫧ |
Barwed; |
U+02306 | ⌆ |
Bcy; |
U+00411 | Б |
Because; |
U+02235 | ∵ |
Bernoullis; |
U+0212C | ℬ |
Beta; |
U+00392 | Β |
Bfr; |
U+1D505 | 𝔅 |
Bopf; |
U+1D539 | 𝔹 |
Breve; |
U+002D8 | ˘ |
Bscr; |
U+0212C | ℬ |
Bumpeq; |
U+0224E | ≎ |
CHcy; |
U+00427 | Ч |
COPY; |
U+000A9 | © |
Cacute; |
U+00106 | Ć |
Cap; |
U+022D2 | ⋒ |
CapitalDifferentialD; |
U+02145 | ⅅ |
Cayleys; |
U+0212D | ℭ |
Ccaron; |
U+0010C | Č |
Ccedil; |
U+000C7 | Ç |
Ccirc; |
U+00108 | Ĉ |
Cconint; |
U+02230 | ∰ |
Cdot; |
U+0010A | Ċ |
Cedilla; |
U+000B8 | ¸ |
CenterDot; |
U+000B7 | · |
Cfr; |
U+0212D | ℭ |
Chi; |
U+003A7 | Χ |
CircleDot; |
U+02299 | ⊙ |
CircleMinus; |
U+02296 | ⊖ |
CirclePlus; |
U+02295 | ⊕ |
CircleTimes; |
U+02297 | ⊗ |
ClockwiseContourIntegral; |
U+02232 | ∲ |
CloseCurlyDoubleQuote; |
U+0201D | ” |
CloseCurlyQuote; |
U+02019 | ’ |
Colon; |
U+02237 | ∷ |
Colone; |
U+02A74 | ⩴ |
Congruent; |
U+02261 | ≡ |
Conint; |
U+0222F | ∯ |
ContourIntegral; |
U+0222E | ∮ |
Copf; |
U+02102 | ℂ |
Coproduct; |
U+02210 | ∐ |
CounterClockwiseContourIntegral; |
U+02233 | ∳ |
Cross; |
U+02A2F | ⨯ |
Cscr; |
U+1D49E | 𝒞 |
Cup; |
U+022D3 | ⋓ |
CupCap; |
U+0224D | ≍ |
DD; |
U+02145 | ⅅ |
DDotrahd; |
U+02911 | ⤑ |
DJcy; |
U+00402 | Ђ |
DScy; |
U+00405 | Ѕ |
DZcy; |
U+0040F | Џ |
Dagger; |
U+02021 | ‡ |
Darr; |
U+021A1 | ↡ |
Dashv; |
U+02AE4 | ⫤ |
Dcaron; |
U+0010E | Ď |
Dcy; |
U+00414 | Д |
Del; |
U+02207 | ∇ |
Delta; |
U+00394 | Δ |
Dfr; |
U+1D507 | 𝔇 |
DiacriticalAcute; |
U+000B4 | ´ |
DiacriticalDot; |
U+002D9 | ˙ |
DiacriticalDoubleAcute; |
U+002DD | ˝ |
DiacriticalGrave; |
U+00060 | ` |
DiacriticalTilde; |
U+002DC | ˜ |
Diamond; |
U+022C4 | ⋄ |
DifferentialD; |
U+02146 | ⅆ |
Dopf; |
U+1D53B | 𝔻 |
Dot; |
U+000A8 | ¨ |
DotDot; |
U+020DC | ◌⃜ |
DotEqual; |
U+02250 | ≐ |
DoubleContourIntegral; |
U+0222F | ∯ |
DoubleDot; |
U+000A8 | ¨ |
DoubleDownArrow; |
U+021D3 | ⇓ |
DoubleLeftArrow; |
U+021D0 | ⇐ |
DoubleLeftRightArrow; |
U+021D4 | ⇔ |
DoubleLeftTee; |
U+02AE4 | ⫤ |
DoubleLongLeftArrow; |
U+027F8 | ⟸ |
DoubleLongLeftRightArrow; |
U+027FA | ⟺ |
DoubleLongRightArrow; |
U+027F9 | ⟹ |
DoubleRightArrow; |
U+021D2 | ⇒ |
DoubleRightTee; |
U+022A8 | ⊨ |
DoubleUpArrow; |
U+021D1 | ⇑ |
DoubleUpDownArrow; |
U+021D5 | ⇕ |
DoubleVerticalBar; |
U+02225 | ∥ |
DownArrow; |
U+02193 | ↓ |
DownArrowBar; |
U+02913 | ⤓ |
DownArrowUpArrow; |
U+021F5 | ⇵ |
DownBreve; |
U+00311 | ◌̑ |
DownLeftRightVector; |
U+02950 | ⥐ |
DownLeftTeeVector; |
U+0295E | ⥞ |
DownLeftVector; |
U+021BD | ↽ |
DownLeftVectorBar; |
U+02956 | ⥖ |
DownRightTeeVector; |
U+0295F | ⥟ |
DownRightVector; |
U+021C1 | ⇁ |
DownRightVectorBar; |
U+02957 | ⥗ |
DownTee; |
U+022A4 | ⊤ |
DownTeeArrow; |
U+021A7 | ↧ |
Downarrow; |
U+021D3 | ⇓ |
Dscr; |
U+1D49F | 𝒟 |
Dstrok; |
U+00110 | Đ |
ENG; |
U+0014A | Ŋ |
ETH; |
U+000D0 | Ð |
Eacute; |
U+000C9 | É |
Ecaron; |
U+0011A | Ě |
Ecirc; |
U+000CA | Ê |
Ecy; |
U+0042D | Э |
Edot; |
U+00116 | Ė |
Efr; |
U+1D508 | 𝔈 |
Egrave; |
U+000C8 | È |
Element; |
U+02208 | ∈ |
Emacr; |
U+00112 | Ē |
EmptySmallSquare; |
U+025FB | ◻ |
EmptyVerySmallSquare; |
U+025AB | ▫ |
Eogon; |
U+00118 | Ę |
Eopf; |
U+1D53C | 𝔼 |
Epsilon; |
U+00395 | Ε |
Equal; |
U+02A75 | ⩵ |
EqualTilde; |
U+02242 | ≂ |
Equilibrium; |
U+021CC | ⇌ |
Escr; |
U+02130 | ℰ |
Esim; |
U+02A73 | ⩳ |
Eta; |
U+00397 | Η |
Euml; |
U+000CB | Ë |
Exists; |
U+02203 | ∃ |
ExponentialE; |
U+02147 | ⅇ |
Fcy; |
U+00424 | Ф |
Ffr; |
U+1D509 | 𝔉 |
FilledSmallSquare; |
U+025FC | ◼ |
FilledVerySmallSquare; |
U+025AA | ▪ |
Fopf; |
U+1D53D | 𝔽 |
ForAll; |
U+02200 | ∀ |
Fouriertrf; |
U+02131 | ℱ |
Fscr; |
U+02131 | ℱ |
GJcy; |
U+00403 | Ѓ |
GT; |
U+0003E | > |
Gamma; |
U+00393 | Γ |
Gammad; |
U+003DC | Ϝ |
Gbreve; |
U+0011E | Ğ |
Gcedil; |
U+00122 | Ģ |
Gcirc; |
U+0011C | Ĝ |
Gcy; |
U+00413 | Г |
Gdot; |
U+00120 | Ġ |
Gfr; |
U+1D50A | 𝔊 |
Gg; |
U+022D9 | ⋙ |
Gopf; |
U+1D53E | 𝔾 |
GreaterEqual; |
U+02265 | ≥ |
GreaterEqualLess; |
U+022DB | ⋛ |
GreaterFullEqual; |
U+02267 | ≧ |
GreaterGreater; |
U+02AA2 | ⪢ |
GreaterLess; |
U+02277 | ≷ |
GreaterSlantEqual; |
U+02A7E | ⩾ |
GreaterTilde; |
U+02273 | ≳ |
Gscr; |
U+1D4A2 | 𝒢 |
Gt; |
U+0226B | ≫ |
HARDcy; |
U+0042A | Ъ |
Hacek; |
U+002C7 | ˇ |
Hat; |
U+0005E | ^ |
Hcirc; |
U+00124 | Ĥ |
Hfr; |
U+0210C | ℌ |
HilbertSpace; |
U+0210B | ℋ |
Hopf; |
U+0210D | ℍ |
HorizontalLine; |
U+02500 | ─ |
Hscr; |
U+0210B | ℋ |
Hstrok; |
U+00126 | Ħ |
HumpDownHump; |
U+0224E | ≎ |
HumpEqual; |
U+0224F | ≏ |
IEcy; |
U+00415 | Е |
IJlig; |
U+00132 | IJ |
IOcy; |
U+00401 | Ё |
Iacute; |
U+000CD | Í |
Icirc; |
U+000CE | Î |
Icy; |
U+00418 | И |
Idot; |
U+00130 | İ |
Ifr; |
U+02111 | ℑ |
Igrave; |
U+000CC | Ì |
Im; |
U+02111 | ℑ |
Imacr; |
U+0012A | Ī |
ImaginaryI; |
U+02148 | ⅈ |
Implies; |
U+021D2 | ⇒ |
Int; |
U+0222C | ∬ |
Integral; |
U+0222B | ∫ |
Intersection; |
U+022C2 | ⋂ |
InvisibleComma; |
U+02063 | |
InvisibleTimes; |
U+02062 | |
Iogon; |
U+0012E | Į |
Iopf; |
U+1D540 | 𝕀 |
Iota; |
U+00399 | Ι |
Iscr; |
U+02110 | ℐ |
Itilde; |
U+00128 | Ĩ |
Iukcy; |
U+00406 | І |
Iuml; |
U+000CF | Ï |
Jcirc; |
U+00134 | Ĵ |
Jcy; |
U+00419 | Й |
Jfr; |
U+1D50D | 𝔍 |
Jopf; |
U+1D541 | 𝕁 |
Jscr; |
U+1D4A5 | 𝒥 |
Jsercy; |
U+00408 | Ј |
Jukcy; |
U+00404 | Є |
KHcy; |
U+00425 | Х |
KJcy; |
U+0040C | Ќ |
Kappa; |
U+0039A | Κ |
Kcedil; |
U+00136 | Ķ |
Kcy; |
U+0041A | К |
Kfr; |
U+1D50E | 𝔎 |
Kopf; |
U+1D542 | 𝕂 |
Kscr; |
U+1D4A6 | 𝒦 |
LJcy; |
U+00409 | Љ |
LT; |
U+0003C | < |
Lacute; |
U+00139 | Ĺ |
Lambda; |
U+0039B | Λ |
Lang; |
U+027EA | ⟪ |
Laplacetrf; |
U+02112 | ℒ |
Larr; |
U+0219E | ↞ |
Lcaron; |
U+0013D | Ľ |
Lcedil; |
U+0013B | Ļ |
Lcy; |
U+0041B | Л |
LeftAngleBracket; |
U+027E8 | ⟨ |
LeftArrow; |
U+02190 | ← |
LeftArrowBar; |
U+021E4 | ⇤ |
LeftArrowRightArrow; |
U+021C6 | ⇆ |
LeftCeiling; |
U+02308 | ⌈ |
LeftDoubleBracket; |
U+027E6 | ⟦ |
LeftDownTeeVector; |
U+02961 | ⥡ |
LeftDownVector; |
U+021C3 | ⇃ |
LeftDownVectorBar; |
U+02959 | ⥙ |
LeftFloor; |
U+0230A | ⌊ |
LeftRightArrow; |
U+02194 | ↔ |
LeftRightVector; |
U+0294E | ⥎ |
LeftTee; |
U+022A3 | ⊣ |
LeftTeeArrow; |
U+021A4 | ↤ |
LeftTeeVector; |
U+0295A | ⥚ |
LeftTriangle; |
U+022B2 | ⊲ |
LeftTriangleBar; |
U+029CF | ⧏ |
LeftTriangleEqual; |
U+022B4 | ⊴ |
LeftUpDownVector; |
U+02951 | ⥑ |
LeftUpTeeVector; |
U+02960 | ⥠ |
LeftUpVector; |
U+021BF | ↿ |
LeftUpVectorBar; |
U+02958 | ⥘ |
LeftVector; |
U+021BC | ↼ |
LeftVectorBar; |
U+02952 | ⥒ |
Leftarrow; |
U+021D0 | ⇐ |
Leftrightarrow; |
U+021D4 | ⇔ |
LessEqualGreater; |
U+022DA | ⋚ |
LessFullEqual; |
U+02266 | ≦ |
LessGreater; |
U+02276 | ≶ |
LessLess; |
U+02AA1 | ⪡ |
LessSlantEqual; |
U+02A7D | ⩽ |
LessTilde; |
U+02272 | ≲ |
Lfr; |
U+1D50F | 𝔏 |
Ll; |
U+022D8 | ⋘ |
Lleftarrow; |
U+021DA | ⇚ |
Lmidot; |
U+0013F | Ŀ |
LongLeftArrow; |
U+027F5 | ⟵ |
LongLeftRightArrow; |
U+027F7 | ⟷ |
LongRightArrow; |
U+027F6 | ⟶ |
Longleftarrow; |
U+027F8 | ⟸ |
Longleftrightarrow; |
U+027FA | ⟺ |
Longrightarrow; |
U+027F9 | ⟹ |
Lopf; |
U+1D543 | 𝕃 |
LowerLeftArrow; |
U+02199 | ↙ |
LowerRightArrow; |
U+02198 | ↘ |
Lscr; |
U+02112 | ℒ |
Lsh; |
U+021B0 | ↰ |
Lstrok; |
U+00141 | Ł |
Lt; |
U+0226A | ≪ |
Map; |
U+02905 | ⤅ |
Mcy; |
U+0041C | М |
MediumSpace; |
U+0205F | |
Mellintrf; |
U+02133 | ℳ |
Mfr; |
U+1D510 | 𝔐 |
MinusPlus; |
U+02213 | ∓ |
Mopf; |
U+1D544 | 𝕄 |
Mscr; |
U+02133 | ℳ |
Mu; |
U+0039C | Μ |
NJcy; |
U+0040A | Њ |
Nacute; |
U+00143 | Ń |
Ncaron; |
U+00147 | Ň |
Ncedil; |
U+00145 | Ņ |
Ncy; |
U+0041D | Н |
NegativeMediumSpace; |
U+0200B | |
NegativeThickSpace; |
U+0200B | |
NegativeThinSpace; |
U+0200B | |
NegativeVeryThinSpace; |
U+0200B | |
NestedGreaterGreater; |
U+0226B | ≫ |
NestedLessLess; |
U+0226A | ≪ |
NewLine; |
U+0000A | ␊ |
Nfr; |
U+1D511 | 𝔑 |
NoBreak; |
U+02060 | |
NonBreakingSpace; |
U+000A0 | |
Nopf; |
U+02115 | ℕ |
Not; |
U+02AEC | ⫬ |
NotCongruent; |
U+02262 | ≢ |
NotCupCap; |
U+0226D | ≭ |
NotDoubleVerticalBar; |
U+02226 | ∦ |
NotElement; |
U+02209 | ∉ |
NotEqual; |
U+02260 | ≠ |
NotEqualTilde; |
U+02242 U+00338 | ≂̸ |
NotExists; |
U+02204 | ∄ |
NotGreater; |
U+0226F | ≯ |
NotGreaterEqual; |
U+02271 | ≱ |
NotGreaterFullEqual; |
U+02267 U+00338 | ≧̸ |
NotGreaterGreater; |
U+0226B U+00338 | ≫̸ |
NotGreaterLess; |
U+02279 | ≹ |
NotGreaterSlantEqual; |
U+02A7E U+00338 | ⩾̸ |
NotGreaterTilde; |
U+02275 | ≵ |
NotHumpDownHump; |
U+0224E U+00338 | ≎̸ |
NotHumpEqual; |
U+0224F U+00338 | ≏̸ |
NotLeftTriangle; |
U+022EA | ⋪ |
NotLeftTriangleBar; |
U+029CF U+00338 | ⧏̸ |
NotLeftTriangleEqual; |
U+022EC | ⋬ |
NotLess; |
U+0226E | ≮ |
NotLessEqual; |
U+02270 | ≰ |
NotLessGreater; |
U+02278 | ≸ |
NotLessLess; |
U+0226A U+00338 | ≪̸ |
NotLessSlantEqual; |
U+02A7D U+00338 | ⩽̸ |
NotLessTilde; |
U+02274 | ≴ |
NotNestedGreaterGreater; |
U+02AA2 U+00338 | ⪢̸ |
NotNestedLessLess; |
U+02AA1 U+00338 | ⪡̸ |
NotPrecedes; |
U+02280 | ⊀ |
NotPrecedesEqual; |
U+02AAF U+00338 | ⪯̸ |
NotPrecedesSlantEqual; |
U+022E0 | ⋠ |
NotReverseElement; |
U+0220C | ∌ |
NotRightTriangle; |
U+022EB | ⋫ |
NotRightTriangleBar; |
U+029D0 U+00338 | ⧐̸ |
NotRightTriangleEqual; |
U+022ED | ⋭ |
NotSquareSubset; |
U+0228F U+00338 | ⊏̸ |
NotSquareSubsetEqual; |
U+022E2 | ⋢ |
NotSquareSuperset; |
U+02290 U+00338 | ⊐̸ |
NotSquareSupersetEqual; |
U+022E3 | ⋣ |
NotSubset; |
U+02282 U+020D2 | ⊂⃒ |
NotSubsetEqual; |
U+02288 | ⊈ |
NotSucceeds; |
U+02281 | ⊁ |
NotSucceedsEqual; |
U+02AB0 U+00338 | ⪰̸ |
NotSucceedsSlantEqual; |
U+022E1 | ⋡ |
NotSucceedsTilde; |
U+0227F U+00338 | ≿̸ |
NotSuperset; |
U+02283 U+020D2 | ⊃⃒ |
NotSupersetEqual; |
U+02289 | ⊉ |
NotTilde; |
U+02241 | ≁ |
NotTildeEqual; |
U+02244 | ≄ |
NotTildeFullEqual; |
U+02247 | ≇ |
NotTildeTilde; |
U+02249 | ≉ |
NotVerticalBar; |
U+02224 | ∤ |
Nscr; |
U+1D4A9 | 𝒩 |
Ntilde; |
U+000D1 | Ñ |
Nu; |
U+0039D | Ν |
OElig; |
U+00152 | Œ |
Oacute; |
U+000D3 | Ó |
Ocirc; |
U+000D4 | Ô |
Ocy; |
U+0041E | О |
Odblac; |
U+00150 | Ő |
Ofr; |
U+1D512 | 𝔒 |
Ograve; |
U+000D2 | Ò |
Omacr; |
U+0014C | Ō |
Omega; |
U+003A9 | Ω |
Omicron; |
U+0039F | Ο |
Oopf; |
U+1D546 | 𝕆 |
OpenCurlyDoubleQuote; |
U+0201C | “ |
OpenCurlyQuote; |
U+02018 | ‘ |
Or; |
U+02A54 | ⩔ |
Oscr; |
U+1D4AA | 𝒪 |
Oslash; |
U+000D8 | Ø |
Otilde; |
U+000D5 | Õ |
Otimes; |
U+02A37 | ⨷ |
Ouml; |
U+000D6 | Ö |
OverBar; |
U+0203E | ‾ |
OverBrace; |
U+023DE | ⏞ |
OverBracket; |
U+023B4 | ⎴ |
OverParenthesis; |
U+023DC | ⏜ |
PartialD; |
U+02202 | ∂ |
Pcy; |
U+0041F | П |
Pfr; |
U+1D513 | 𝔓 |
Phi; |
U+003A6 | Φ |
Pi; |
U+003A0 | Π |
PlusMinus; |
U+000B1 | ± |
Poincareplane; |
U+0210C | ℌ |
Popf; |
U+02119 | ℙ |
Pr; |
U+02ABB | ⪻ |
Precedes; |
U+0227A | ≺ |
PrecedesEqual; |
U+02AAF | ⪯ |
PrecedesSlantEqual; |
U+0227C | ≼ |
PrecedesTilde; |
U+0227E | ≾ |
Prime; |
U+02033 | ″ |
Product; |
U+0220F | ∏ |
Proportion; |
U+02237 | ∷ |
Proportional; |
U+0221D | ∝ |
Pscr; |
U+1D4AB | 𝒫 |
Psi; |
U+003A8 | Ψ |
QUOT; |
U+00022 | " |
Qfr; |
U+1D514 | 𝔔 |
Qopf; |
U+0211A | ℚ |
Qscr; |
U+1D4AC | 𝒬 |
RBarr; |
U+02910 | ⤐ |
REG; |
U+000AE | ® |
Racute; |
U+00154 | Ŕ |
Rang; |
U+027EB | ⟫ |
Rarr; |
U+021A0 | ↠ |
Rarrtl; |
U+02916 | ⤖ |
Rcaron; |
U+00158 | Ř |
Rcedil; |
U+00156 | Ŗ |
Rcy; |
U+00420 | Р |
Re; |
U+0211C | ℜ |
ReverseElement; |
U+0220B | ∋ |
ReverseEquilibrium; |
U+021CB | ⇋ |
ReverseUpEquilibrium; |
U+0296F | ⥯ |
Rfr; |
U+0211C | ℜ |
Rho; |
U+003A1 | Ρ |
RightAngleBracket; |
U+027E9 | ⟩ |
RightArrow; |
U+02192 | → |
RightArrowBar; |
U+021E5 | ⇥ |
RightArrowLeftArrow; |
U+021C4 | ⇄ |
RightCeiling; |
U+02309 | ⌉ |
RightDoubleBracket; |
U+027E7 | ⟧ |
RightDownTeeVector; |
U+0295D | ⥝ |
RightDownVector; |
U+021C2 | ⇂ |
RightDownVectorBar; |
U+02955 | ⥕ |
RightFloor; |
U+0230B | ⌋ |
RightTee; |
U+022A2 | ⊢ |
RightTeeArrow; |
U+021A6 | ↦ |
RightTeeVector; |
U+0295B | ⥛ |
RightTriangle; |
U+022B3 | ⊳ |
RightTriangleBar; |
U+029D0 | ⧐ |
RightTriangleEqual; |
U+022B5 | ⊵ |
RightUpDownVector; |
U+0294F | ⥏ |
RightUpTeeVector; |
U+0295C | ⥜ |
RightUpVector; |
U+021BE | ↾ |
RightUpVectorBar; |
U+02954 | ⥔ |
RightVector; |
U+021C0 | ⇀ |
RightVectorBar; |
U+02953 | ⥓ |
Rightarrow; |
U+021D2 | ⇒ |
Ropf; |
U+0211D | ℝ |
RoundImplies; |
U+02970 | ⥰ |
Rrightarrow; |
U+021DB | ⇛ |
Rscr; |
U+0211B | ℛ |
Rsh; |
U+021B1 | ↱ |
RuleDelayed; |
U+029F4 | ⧴ |
SHCHcy; |
U+00429 | Щ |
SHcy; |
U+00428 | Ш |
SOFTcy; |
U+0042C | Ь |
Sacute; |
U+0015A | Ś |
Sc; |
U+02ABC | ⪼ |
Scaron; |
U+00160 | Š |
Scedil; |
U+0015E | Ş |
Scirc; |
U+0015C | Ŝ |
Scy; |
U+00421 | С |
Sfr; |
U+1D516 | 𝔖 |
ShortDownArrow; |
U+02193 | ↓ |
ShortLeftArrow; |
U+02190 | ← |
ShortRightArrow; |
U+02192 | → |
ShortUpArrow; |
U+02191 | ↑ |
Sigma; |
U+003A3 | Σ |
SmallCircle; |
U+02218 | ∘ |
Sopf; |
U+1D54A | 𝕊 |
Sqrt; |
U+0221A | √ |
Square; |
U+025A1 | □ |
SquareIntersection; |
U+02293 | ⊓ |
SquareSubset; |
U+0228F | ⊏ |
SquareSubsetEqual; |
U+02291 | ⊑ |
SquareSuperset; |
U+02290 | ⊐ |
SquareSupersetEqual; |
U+02292 | ⊒ |
SquareUnion; |
U+02294 | ⊔ |
Sscr; |
U+1D4AE | 𝒮 |
Star; |
U+022C6 | ⋆ |
Sub; |
U+022D0 | ⋐ |
Subset; |
U+022D0 | ⋐ |
SubsetEqual; |
U+02286 | ⊆ |
Succeeds; |
U+0227B | ≻ |
SucceedsEqual; |
U+02AB0 | ⪰ |
SucceedsSlantEqual; |
U+0227D | ≽ |
SucceedsTilde; |
U+0227F | ≿ |
SuchThat; |
U+0220B | ∋ |
Sum; |
U+02211 | ∑ |
Sup; |
U+022D1 | ⋑ |
Superset; |
U+02283 | ⊃ |
SupersetEqual; |
U+02287 | ⊇ |
Supset; |
U+022D1 | ⋑ |
THORN; |
U+000DE | Þ |
TRADE; |
U+02122 | ™ |
TSHcy; |
U+0040B | Ћ |
TScy; |
U+00426 | Ц |
Tab; |
U+00009 | ␉ |
Tau; |
U+003A4 | Τ |
Tcaron; |
U+00164 | Ť |
Tcedil; |
U+00162 | Ţ |
Tcy; |
U+00422 | Т |
Tfr; |
U+1D517 | 𝔗 |
Therefore; |
U+02234 | ∴ |
Theta; |
U+00398 | Θ |
ThickSpace; |
U+0205F U+0200A | |
ThinSpace; |
U+02009 | |
Tilde; |
U+0223C | ∼ |
TildeEqual; |
U+02243 | ≃ |
TildeFullEqual; |
U+02245 | ≅ |
TildeTilde; |
U+02248 | ≈ |
Topf; |
U+1D54B | 𝕋 |
TripleDot; |
U+020DB | ◌⃛ |
Tscr; |
U+1D4AF | 𝒯 |
Tstrok; |
U+00166 | Ŧ |
Uacute; |
U+000DA | Ú |
Uarr; |
U+0219F | ↟ |
Uarrocir; |
U+02949 | ⥉ |
Ubrcy; |
U+0040E | Ў |
Ubreve; |
U+0016C | Ŭ |
Ucirc; |
U+000DB | Û |
Ucy; |
U+00423 | У |
Udblac; |
U+00170 | Ű |
Ufr; |
U+1D518 | 𝔘 |
Ugrave; |
U+000D9 | Ù |
Umacr; |
U+0016A | Ū |
UnderBar; |
U+0005F | _ |
UnderBrace; |
U+023DF | ⏟ |
UnderBracket; |
U+023B5 | ⎵ |
UnderParenthesis; |
U+023DD | ⏝ |
Union; |
U+022C3 | ⋃ |
UnionPlus; |
U+0228E | ⊎ |
Uogon; |
U+00172 | Ų |
Uopf; |
U+1D54C | 𝕌 |
UpArrow; |
U+02191 | ↑ |
UpArrowBar; |
U+02912 | ⤒ |
UpArrowDownArrow; |
U+021C5 | ⇅ |
UpDownArrow; |
U+02195 | ↕ |
UpEquilibrium; |
U+0296E | ⥮ |
UpTee; |
U+022A5 | ⊥ |
UpTeeArrow; |
U+021A5 | ↥ |
Uparrow; |
U+021D1 | ⇑ |
Updownarrow; |
U+021D5 | ⇕ |
UpperLeftArrow; |
U+02196 | ↖ |
UpperRightArrow; |
U+02197 | ↗ |
Upsi; |
U+003D2 | ϒ |
Upsilon; |
U+003A5 | Υ |
Uring; |
U+0016E | Ů |
Uscr; |
U+1D4B0 | 𝒰 |
Utilde; |
U+00168 | Ũ |
Uuml; |
U+000DC | Ü |
VDash; |
U+022AB | ⊫ |
Vbar; |
U+02AEB | ⫫ |
Vcy; |
U+00412 | В |
Vdash; |
U+022A9 | ⊩ |
Vdashl; |
U+02AE6 | ⫦ |
Vee; |
U+022C1 | ⋁ |
Verbar; |
U+02016 | ‖ |
Vert; |
U+02016 | ‖ |
VerticalBar; |
U+02223 | ∣ |
VerticalLine; |
U+0007C | | |
VerticalSeparator; |
U+02758 | ❘ |
VerticalTilde; |
U+02240 | ≀ |
VeryThinSpace; |
U+0200A | |
Vfr; |
U+1D519 | 𝔙 |
Vopf; |
U+1D54D | 𝕍 |
Vscr; |
U+1D4B1 | 𝒱 |
Vvdash; |
U+022AA | ⊪ |
Wcirc; |
U+00174 | Ŵ |
Wedge; |
U+022C0 | ⋀ |
Wfr; |
U+1D51A | 𝔚 |
Wopf; |
U+1D54E | 𝕎 |
Wscr; |
U+1D4B2 | 𝒲 |
Xfr; |
U+1D51B | 𝔛 |
Xi; |
U+0039E | Ξ |
Xopf; |
U+1D54F | 𝕏 |
Xscr; |
U+1D4B3 | 𝒳 |
YAcy; |
U+0042F | Я |
YIcy; |
U+00407 | Ї |
YUcy; |
U+0042E | Ю |
Yacute; |
U+000DD | Ý |
Ycirc; |
U+00176 | Ŷ |
Ycy; |
U+0042B | Ы |
Yfr; |
U+1D51C | 𝔜 |
Yopf; |
U+1D550 | 𝕐 |
Yscr; |
U+1D4B4 | 𝒴 |
Yuml; |
U+00178 | Ÿ |
ZHcy; |
U+00416 | Ж |
Zacute; |
U+00179 | Ź |
Zcaron; |
U+0017D | Ž |
Zcy; |
U+00417 | З |
Zdot; |
U+0017B | Ż |
ZeroWidthSpace; |
U+0200B | |
Zeta; |
U+00396 | Ζ |
Zfr; |
U+02128 | ℨ |
Zopf; |
U+02124 | ℤ |
Zscr; |
U+1D4B5 | 𝒵 |
aacute; |
U+000E1 | á |
abreve; |
U+00103 | ă |
ac; |
U+0223E | ∾ |
acE; |
U+0223E U+00333 | ∾̳ |
acd; |
U+0223F | ∿ |
acirc; |
U+000E2 | â |
acute; |
U+000B4 | ´ |
acy; |
U+00430 | а |
aelig; |
U+000E6 | æ |
af; |
U+02061 | |
afr; |
U+1D51E | 𝔞 |
agrave; |
U+000E0 | à |
alefsym; |
U+02135 | ℵ |
aleph; |
U+02135 | ℵ |
alpha; |
U+003B1 | α |
amacr; |
U+00101 | ā |
amalg; |
U+02A3F | ⨿ |
amp; |
U+00026 | & |
and; |
U+02227 | ∧ |
andand; |
U+02A55 | ⩕ |
andd; |
U+02A5C | ⩜ |
andslope; |
U+02A58 | ⩘ |
andv; |
U+02A5A | ⩚ |
ang; |
U+02220 | ∠ |
ange; |
U+029A4 | ⦤ |
angle; |
U+02220 | ∠ |
angmsd; |
U+02221 | ∡ |
angmsdaa; |
U+029A8 | ⦨ |
angmsdab; |
U+029A9 | ⦩ |
angmsdac; |
U+029AA | ⦪ |
angmsdad; |
U+029AB | ⦫ |
angmsdae; |
U+029AC | ⦬ |
angmsdaf; |
U+029AD | ⦭ |
angmsdag; |
U+029AE | ⦮ |
angmsdah; |
U+029AF | ⦯ |
angrt; |
U+0221F | ∟ |
angrtvb; |
U+022BE | ⊾ |
angrtvbd; |
U+0299D | ⦝ |
angsph; |
U+02222 | ∢ |
angst; |
U+000C5 | Å |
angzarr; |
U+0237C | ⍼ |
aogon; |
U+00105 | ą |
aopf; |
U+1D552 | 𝕒 |
ap; |
U+02248 | ≈ |
apE; |
U+02A70 | ⩰ |
apacir; |
U+02A6F | ⩯ |
ape; |
U+0224A | ≊ |
apid; |
U+0224B | ≋ |
apos; |
U+00027 | ' |
approx; |
U+02248 | ≈ |
approxeq; |
U+0224A | ≊ |
aring; |
U+000E5 | å |
ascr; |
U+1D4B6 | 𝒶 |
ast; |
U+0002A | * |
asymp; |
U+02248 | ≈ |
asympeq; |
U+0224D | ≍ |
atilde; |
U+000E3 | ã |
auml; |
U+000E4 | ä |
awconint; |
U+02233 | ∳ |
awint; |
U+02A11 | ⨑ |
bNot; |
U+02AED | ⫭ |
backcong; |
U+0224C | ≌ |
backepsilon; |
U+003F6 | ϶ |
backprime; |
U+02035 | ‵ |
backsim; |
U+0223D | ∽ |
backsimeq; |
U+022CD | ⋍ |
barvee; |
U+022BD | ⊽ |
barwed; |
U+02305 | ⌅ |
barwedge; |
U+02305 | ⌅ |
bbrk; |
U+023B5 | ⎵ |
bbrktbrk; |
U+023B6 | ⎶ |
bcong; |
U+0224C | ≌ |
bcy; |
U+00431 | б |
bdquo; |
U+0201E | „ |
becaus; |
U+02235 | ∵ |
because; |
U+02235 | ∵ |
bemptyv; |
U+029B0 | ⦰ |
bepsi; |
U+003F6 | ϶ |
bernou; |
U+0212C | ℬ |
beta; |
U+003B2 | β |
beth; |
U+02136 | ℶ |
between; |
U+0226C | ≬ |
bfr; |
U+1D51F | 𝔟 |
bigcap; |
U+022C2 | ⋂ |
bigcirc; |
U+025EF | ◯ |
bigcup; |
U+022C3 | ⋃ |
bigodot; |
U+02A00 | ⨀ |
bigoplus; |
U+02A01 | ⨁ |
bigotimes; |
U+02A02 | ⨂ |
bigsqcup; |
U+02A06 | ⨆ |
bigstar; |
U+02605 | ★ |
bigtriangledown; |
U+025BD | ▽ |
bigtriangleup; |
U+025B3 | △ |
biguplus; |
U+02A04 | ⨄ |
bigvee; |
U+022C1 | ⋁ |
bigwedge; |
U+022C0 | ⋀ |
bkarow; |
U+0290D | ⤍ |
blacklozenge; |
U+029EB | ⧫ |
blacksquare; |
U+025AA | ▪ |
blacktriangle; |
U+025B4 | ▴ |
blacktriangledown; |
U+025BE | ▾ |
blacktriangleleft; |
U+025C2 | ◂ |
blacktriangleright; |
U+025B8 | ▸ |
blank; |
U+02423 | ␣ |
blk12; |
U+02592 | ▒ |
blk14; |
U+02591 | ░ |
blk34; |
U+02593 | ▓ |
block; |
U+02588 | █ |
bne; |
U+0003D U+020E5 | =⃥ |
bnequiv; |
U+02261 U+020E5 | ≡⃥ |
bnot; |
U+02310 | ⌐ |
bopf; |
U+1D553 | 𝕓 |
bot; |
U+022A5 | ⊥ |
bottom; |
U+022A5 | ⊥ |
bowtie; |
U+022C8 | ⋈ |
boxDL; |
U+02557 | ╗ |
boxDR; |
U+02554 | ╔ |
boxDl; |
U+02556 | ╖ |
boxDr; |
U+02553 | ╓ |
boxH; |
U+02550 | ═ |
boxHD; |
U+02566 | ╦ |
boxHU; |
U+02569 | ╩ |
boxHd; |
U+02564 | ╤ |
boxHu; |
U+02567 | ╧ |
boxUL; |
U+0255D | ╝ |
boxUR; |
U+0255A | ╚ |
boxUl; |
U+0255C | ╜ |
boxUr; |
U+02559 | ╙ |
boxV; |
U+02551 | ║ |
boxVH; |
U+0256C | ╬ |
boxVL; |
U+02563 | ╣ |
boxVR; |
U+02560 | ╠ |
boxVh; |
U+0256B | ╫ |
boxVl; |
U+02562 | ╢ |
boxVr; |
U+0255F | ╟ |
boxbox; |
U+029C9 | ⧉ |
boxdL; |
U+02555 | ╕ |
boxdR; |
U+02552 | ╒ |
boxdl; |
U+02510 | ┐ |
boxdr; |
U+0250C | ┌ |
boxh; |
U+02500 | ─ |
boxhD; |
U+02565 | ╥ |
boxhU; |
U+02568 | ╨ |
boxhd; |
U+0252C | ┬ |
boxhu; |
U+02534 | ┴ |
boxminus; |
U+0229F | ⊟ |
boxplus; |
U+0229E | ⊞ |
boxtimes; |
U+022A0 | ⊠ |
boxuL; |
U+0255B | ╛ |
boxuR; |
U+02558 | ╘ |
boxul; |
U+02518 | ┘ |
boxur; |
U+02514 | └ |
boxv; |
U+02502 | │ |
boxvH; |
U+0256A | ╪ |
boxvL; |
U+02561 | ╡ |
boxvR; |
U+0255E | ╞ |
boxvh; |
U+0253C | ┼ |
boxvl; |
U+02524 | ┤ |
boxvr; |
U+0251C | ├ |
bprime; |
U+02035 | ‵ |
breve; |
U+002D8 | ˘ |
brvbar; |
U+000A6 | ¦ |
bscr; |
U+1D4B7 | 𝒷 |
bsemi; |
U+0204F | ⁏ |
bsim; |
U+0223D | ∽ |
bsime; |
U+022CD | ⋍ |
bsol; |
U+0005C | \ |
bsolb; |
U+029C5 | ⧅ |
bsolhsub; |
U+027C8 | ⟈ |
bull; |
U+02022 | • |
bullet; |
U+02022 | • |
bump; |
U+0224E | ≎ |
bumpE; |
U+02AAE | ⪮ |
bumpe; |
U+0224F | ≏ |
bumpeq; |
U+0224F | ≏ |
cacute; |
U+00107 | ć |
cap; |
U+02229 | ∩ |
capand; |
U+02A44 | ⩄ |
capbrcup; |
U+02A49 | ⩉ |
capcap; |
U+02A4B | ⩋ |
capcup; |
U+02A47 | ⩇ |
capdot; |
U+02A40 | ⩀ |
caps; |
U+02229 U+0FE00 | ∩︀ |
caret; |
U+02041 | ⁁ |
caron; |
U+002C7 | ˇ |
ccaps; |
U+02A4D | ⩍ |
ccaron; |
U+0010D | č |
ccedil; |
U+000E7 | ç |
ccirc; |
U+00109 | ĉ |
ccups; |
U+02A4C | ⩌ |
ccupssm; |
U+02A50 | ⩐ |
cdot; |
U+0010B | ċ |
cedil; |
U+000B8 | ¸ |
cemptyv; |
U+029B2 | ⦲ |
cent; |
U+000A2 | ¢ |
centerdot; |
U+000B7 | · |
cfr; |
U+1D520 | 𝔠 |
chcy; |
U+00447 | ч |
check; |
U+02713 | ✓ |
checkmark; |
U+02713 | ✓ |
chi; |
U+003C7 | χ |
cir; |
U+025CB | ○ |
cirE; |
U+029C3 | ⧃ |
circ; |
U+002C6 | ˆ |
circeq; |
U+02257 | ≗ |
circlearrowleft; |
U+021BA | ↺ |
circlearrowright; |
U+021BB | ↻ |
circledR; |
U+000AE | ® |
circledS; |
U+024C8 | Ⓢ |
circledast; |
U+0229B | ⊛ |
circledcirc; |
U+0229A | ⊚ |
circleddash; |
U+0229D | ⊝ |
cire; |
U+02257 | ≗ |
cirfnint; |
U+02A10 | ⨐ |
cirmid; |
U+02AEF | ⫯ |
cirscir; |
U+029C2 | ⧂ |
clubs; |
U+02663 | ♣ |
clubsuit; |
U+02663 | ♣ |
colon; |
U+0003A | : |
colone; |
U+02254 | ≔ |
coloneq; |
U+02254 | ≔ |
comma; |
U+0002C | , |
commat; |
U+00040 | @ |
comp; |
U+02201 | ∁ |
compfn; |
U+02218 | ∘ |
complement; |
U+02201 | ∁ |
complexes; |
U+02102 | ℂ |
cong; |
U+02245 | ≅ |
congdot; |
U+02A6D | ⩭ |
conint; |
U+0222E | ∮ |
copf; |
U+1D554 | 𝕔 |
coprod; |
U+02210 | ∐ |
copy; |
U+000A9 | © |
copysr; |
U+02117 | ℗ |
crarr; |
U+021B5 | ↵ |
cross; |
U+02717 | ✗ |
cscr; |
U+1D4B8 | 𝒸 |
csub; |
U+02ACF | ⫏ |
csube; |
U+02AD1 | ⫑ |
csup; |
U+02AD0 | ⫐ |
csupe; |
U+02AD2 | ⫒ |
ctdot; |
U+022EF | ⋯ |
cudarrl; |
U+02938 | ⤸ |
cudarrr; |
U+02935 | ⤵ |
cuepr; |
U+022DE | ⋞ |
cuesc; |
U+022DF | ⋟ |
cularr; |
U+021B6 | ↶ |
cularrp; |
U+0293D | ⤽ |
cup; |
U+0222A | ∪ |
cupbrcap; |
U+02A48 | ⩈ |
cupcap; |
U+02A46 | ⩆ |
cupcup; |
U+02A4A | ⩊ |
cupdot; |
U+0228D | ⊍ |
cupor; |
U+02A45 | ⩅ |
cups; |
U+0222A U+0FE00 | ∪︀ |
curarr; |
U+021B7 | ↷ |
curarrm; |
U+0293C | ⤼ |
curlyeqprec; |
U+022DE | ⋞ |
curlyeqsucc; |
U+022DF | ⋟ |
curlyvee; |
U+022CE | ⋎ |
curlywedge; |
U+022CF | ⋏ |
curren; |
U+000A4 | ¤ |
curvearrowleft; |
U+021B6 | ↶ |
curvearrowright; |
U+021B7 | ↷ |
cuvee; |
U+022CE | ⋎ |
cuwed; |
U+022CF | ⋏ |
cwconint; |
U+02232 | ∲ |
cwint; |
U+02231 | ∱ |
cylcty; |
U+0232D | ⌭ |
dArr; |
U+021D3 | ⇓ |
dHar; |
U+02965 | ⥥ |
dagger; |
U+02020 | † |
daleth; |
U+02138 | ℸ |
darr; |
U+02193 | ↓ |
dash; |
U+02010 | ‐ |
dashv; |
U+022A3 | ⊣ |
dbkarow; |
U+0290F | ⤏ |
dblac; |
U+002DD | ˝ |
dcaron; |
U+0010F | ď |
dcy; |
U+00434 | д |
dd; |
U+02146 | ⅆ |
ddagger; |
U+02021 | ‡ |
ddarr; |
U+021CA | ⇊ |
ddotseq; |
U+02A77 | ⩷ |
deg; |
U+000B0 | ° |
delta; |
U+003B4 | δ |
demptyv; |
U+029B1 | ⦱ |
dfisht; |
U+0297F | ⥿ |
dfr; |
U+1D521 | 𝔡 |
dharl; |
U+021C3 | ⇃ |
dharr; |
U+021C2 | ⇂ |
diam; |
U+022C4 | ⋄ |
diamond; |
U+022C4 | ⋄ |
diamondsuit; |
U+02666 | ♦ |
diams; |
U+02666 | ♦ |
die; |
U+000A8 | ¨ |
digamma; |
U+003DD | ϝ |
disin; |
U+022F2 | ⋲ |
div; |
U+000F7 | ÷ |
divide; |
U+000F7 | ÷ |
divideontimes; |
U+022C7 | ⋇ |
divonx; |
U+022C7 | ⋇ |
djcy; |
U+00452 | ђ |
dlcorn; |
U+0231E | ⌞ |
dlcrop; |
U+0230D | ⌍ |
dollar; |
U+00024 | $ |
dopf; |
U+1D555 | 𝕕 |
dot; |
U+002D9 | ˙ |
doteq; |
U+02250 | ≐ |
doteqdot; |
U+02251 | ≑ |
dotminus; |
U+02238 | ∸ |
dotplus; |
U+02214 | ∔ |
dotsquare; |
U+022A1 | ⊡ |
doublebarwedge; |
U+02306 | ⌆ |
downarrow; |
U+02193 | ↓ |
downdownarrows; |
U+021CA | ⇊ |
downharpoonleft; |
U+021C3 | ⇃ |
downharpoonright; |
U+021C2 | ⇂ |
drbkarow; |
U+02910 | ⤐ |
drcorn; |
U+0231F | ⌟ |
drcrop; |
U+0230C | ⌌ |
dscr; |
U+1D4B9 | 𝒹 |
dscy; |
U+00455 | ѕ |
dsol; |
U+029F6 | ⧶ |
dstrok; |
U+00111 | đ |
dtdot; |
U+022F1 | ⋱ |
dtri; |
U+025BF | ▿ |
dtrif; |
U+025BE | ▾ |
duarr; |
U+021F5 | ⇵ |
duhar; |
U+0296F | ⥯ |
dwangle; |
U+029A6 | ⦦ |
dzcy; |
U+0045F | џ |
dzigrarr; |
U+027FF | ⟿ |
eDDot; |
U+02A77 | ⩷ |
eDot; |
U+02251 | ≑ |
eacute; |
U+000E9 | é |
easter; |
U+02A6E | ⩮ |
ecaron; |
U+0011B | ě |
ecir; |
U+02256 | ≖ |
ecirc; |
U+000EA | ê |
ecolon; |
U+02255 | ≕ |
ecy; |
U+0044D | э |
edot; |
U+00117 | ė |
ee; |
U+02147 | ⅇ |
efDot; |
U+02252 | ≒ |
efr; |
U+1D522 | 𝔢 |
eg; |
U+02A9A | ⪚ |
egrave; |
U+000E8 | è |
egs; |
U+02A96 | ⪖ |
egsdot; |
U+02A98 | ⪘ |
el; |
U+02A99 | ⪙ |
elinters; |
U+023E7 | ⏧ |
ell; |
U+02113 | ℓ |
els; |
U+02A95 | ⪕ |
elsdot; |
U+02A97 | ⪗ |
emacr; |
U+00113 | ē |
empty; |
U+02205 | ∅ |
emptyset; |
U+02205 | ∅ |
emptyv; |
U+02205 | ∅ |
emsp; |
U+02003 | |
emsp13; |
U+02004 | |
emsp14; |
U+02005 | |
eng; |
U+0014B | ŋ |
ensp; |
U+02002 | |
eogon; |
U+00119 | ę |
eopf; |
U+1D556 | 𝕖 |
epar; |
U+022D5 | ⋕ |
eparsl; |
U+029E3 | ⧣ |
eplus; |
U+02A71 | ⩱ |
epsi; |
U+003B5 | ε |
epsilon; |
U+003B5 | ε |
epsiv; |
U+003F5 | ϵ |
eqcirc; |
U+02256 | ≖ |
eqcolon; |
U+02255 | ≕ |
eqsim; |
U+02242 | ≂ |
eqslantgtr; |
U+02A96 | ⪖ |
eqslantless; |
U+02A95 | ⪕ |
equals; |
U+0003D | = |
equest; |
U+0225F | ≟ |
equiv; |
U+02261 | ≡ |
equivDD; |
U+02A78 | ⩸ |
eqvparsl; |
U+029E5 | ⧥ |
erDot; |
U+02253 | ≓ |
erarr; |
U+02971 | ⥱ |
escr; |
U+0212F | ℯ |
esdot; |
U+02250 | ≐ |
esim; |
U+02242 | ≂ |
eta; |
U+003B7 | η |
eth; |
U+000F0 | ð |
euml; |
U+000EB | ë |
euro; |
U+020AC | € |
excl; |
U+00021 | ! |
exist; |
U+02203 | ∃ |
expectation; |
U+02130 | ℰ |
exponentiale; |
U+02147 | ⅇ |
fallingdotseq; |
U+02252 | ≒ |
fcy; |
U+00444 | ф |
female; |
U+02640 | ♀ |
ffilig; |
U+0FB03 | ffi |
fflig; |
U+0FB00 | ff |
ffllig; |
U+0FB04 | ffl |
ffr; |
U+1D523 | 𝔣 |
filig; |
U+0FB01 | fi |
fjlig; |
U+00066 U+0006A | fj |
flat; |
U+0266D | ♭ |
fllig; |
U+0FB02 | fl |
fltns; |
U+025B1 | ▱ |
fnof; |
U+00192 | ƒ |
fopf; |
U+1D557 | 𝕗 |
forall; |
U+02200 | ∀ |
fork; |
U+022D4 | ⋔ |
forkv; |
U+02AD9 | ⫙ |
fpartint; |
U+02A0D | ⨍ |
frac12; |
U+000BD | ½ |
frac13; |
U+02153 | ⅓ |
frac14; |
U+000BC | ¼ |
frac15; |
U+02155 | ⅕ |
frac16; |
U+02159 | ⅙ |
frac18; |
U+0215B | ⅛ |
frac23; |
U+02154 | ⅔ |
frac25; |
U+02156 | ⅖ |
frac34; |
U+000BE | ¾ |
frac35; |
U+02157 | ⅗ |
frac38; |
U+0215C | ⅜ |
frac45; |
U+02158 | ⅘ |
frac56; |
U+0215A | ⅚ |
frac58; |
U+0215D | ⅝ |
frac78; |
U+0215E | ⅞ |
frasl; |
U+02044 | ⁄ |
frown; |
U+02322 | ⌢ |
fscr; |
U+1D4BB | 𝒻 |
gE; |
U+02267 | ≧ |
gEl; |
U+02A8C | ⪌ |
gacute; |
U+001F5 | ǵ |
gamma; |
U+003B3 | γ |
gammad; |
U+003DD | ϝ |
gap; |
U+02A86 | ⪆ |
gbreve; |
U+0011F | ğ |
gcirc; |
U+0011D | ĝ |
gcy; |
U+00433 | г |
gdot; |
U+00121 | ġ |
ge; |
U+02265 | ≥ |
gel; |
U+022DB | ⋛ |
geq; |
U+02265 | ≥ |
geqq; |
U+02267 | ≧ |
geqslant; |
U+02A7E | ⩾ |
ges; |
U+02A7E | ⩾ |
gescc; |
U+02AA9 | ⪩ |
gesdot; |
U+02A80 | ⪀ |
gesdoto; |
U+02A82 | ⪂ |
gesdotol; |
U+02A84 | ⪄ |
gesl; |
U+022DB U+0FE00 | ⋛︀ |
gesles; |
U+02A94 | ⪔ |
gfr; |
U+1D524 | 𝔤 |
gg; |
U+0226B | ≫ |
ggg; |
U+022D9 | ⋙ |
gimel; |
U+02137 | ℷ |
gjcy; |
U+00453 | ѓ |
gl; |
U+02277 | ≷ |
glE; |
U+02A92 | ⪒ |
gla; |
U+02AA5 | ⪥ |
glj; |
U+02AA4 | ⪤ |
gnE; |
U+02269 | ≩ |
gnap; |
U+02A8A | ⪊ |
gnapprox; |
U+02A8A | ⪊ |
gne; |
U+02A88 | ⪈ |
gneq; |
U+02A88 | ⪈ |
gneqq; |
U+02269 | ≩ |
gnsim; |
U+022E7 | ⋧ |
gopf; |
U+1D558 | 𝕘 |
grave; |
U+00060 | ` |
gscr; |
U+0210A | ℊ |
gsim; |
U+02273 | ≳ |
gsime; |
U+02A8E | ⪎ |
gsiml; |
U+02A90 | ⪐ |
gt; |
U+0003E | > |
gtcc; |
U+02AA7 | ⪧ |
gtcir; |
U+02A7A | ⩺ |
gtdot; |
U+022D7 | ⋗ |
gtlPar; |
U+02995 | ⦕ |
gtquest; |
U+02A7C | ⩼ |
gtrapprox; |
U+02A86 | ⪆ |
gtrarr; |
U+02978 | ⥸ |
gtrdot; |
U+022D7 | ⋗ |
gtreqless; |
U+022DB | ⋛ |
gtreqqless; |
U+02A8C | ⪌ |
gtrless; |
U+02277 | ≷ |
gtrsim; |
U+02273 | ≳ |
gvertneqq; |
U+02269 U+0FE00 | ≩︀ |
gvnE; |
U+02269 U+0FE00 | ≩︀ |
hArr; |
U+021D4 | ⇔ |
hairsp; |
U+0200A | |
half; |
U+000BD | ½ |
hamilt; |
U+0210B | ℋ |
hardcy; |
U+0044A | ъ |
harr; |
U+02194 | ↔ |
harrcir; |
U+02948 | ⥈ |
harrw; |
U+021AD | ↭ |
hbar; |
U+0210F | ℏ |
hcirc; |
U+00125 | ĥ |
hearts; |
U+02665 | ♥ |
heartsuit; |
U+02665 | ♥ |
hellip; |
U+02026 | … |
hercon; |
U+022B9 | ⊹ |
hfr; |
U+1D525 | 𝔥 |
hksearow; |
U+02925 | ⤥ |
hkswarow; |
U+02926 | ⤦ |
hoarr; |
U+021FF | ⇿ |
homtht; |
U+0223B | ∻ |
hookleftarrow; |
U+021A9 | ↩ |
hookrightarrow; |
U+021AA | ↪ |
hopf; |
U+1D559 | 𝕙 |
horbar; |
U+02015 | ― |
hscr; |
U+1D4BD | 𝒽 |
hslash; |
U+0210F | ℏ |
hstrok; |
U+00127 | ħ |
hybull; |
U+02043 | ⁃ |
hyphen; |
U+02010 | ‐ |
iacute; |
U+000ED | í |
ic; |
U+02063 | |
icirc; |
U+000EE | î |
icy; |
U+00438 | и |
iecy; |
U+00435 | е |
iexcl; |
U+000A1 | ¡ |
iff; |
U+021D4 | ⇔ |
ifr; |
U+1D526 | 𝔦 |
igrave; |
U+000EC | ì |
ii; |
U+02148 | ⅈ |
iiiint; |
U+02A0C | ⨌ |
iiint; |
U+0222D | ∭ |
iinfin; |
U+029DC | ⧜ |
iiota; |
U+02129 | ℩ |
ijlig; |
U+00133 | ij |
imacr; |
U+0012B | ī |
image; |
U+02111 | ℑ |
imagline; |
U+02110 | ℐ |
imagpart; |
U+02111 | ℑ |
imath; |
U+00131 | ı |
imof; |
U+022B7 | ⊷ |
imped; |
U+001B5 | Ƶ |
in; |
U+02208 | ∈ |
incare; |
U+02105 | ℅ |
infin; |
U+0221E | ∞ |
infintie; |
U+029DD | ⧝ |
inodot; |
U+00131 | ı |
int; |
U+0222B | ∫ |
intcal; |
U+022BA | ⊺ |
integers; |
U+02124 | ℤ |
intercal; |
U+022BA | ⊺ |
intlarhk; |
U+02A17 | ⨗ |
intprod; |
U+02A3C | ⨼ |
iocy; |
U+00451 | ё |
iogon; |
U+0012F | į |
iopf; |
U+1D55A | 𝕚 |
iota; |
U+003B9 | ι |
iprod; |
U+02A3C | ⨼ |
iquest; |
U+000BF | ¿ |
iscr; |
U+1D4BE | 𝒾 |
isin; |
U+02208 | ∈ |
isinE; |
U+022F9 | ⋹ |
isindot; |
U+022F5 | ⋵ |
isins; |
U+022F4 | ⋴ |
isinsv; |
U+022F3 | ⋳ |
isinv; |
U+02208 | ∈ |
it; |
U+02062 | |
itilde; |
U+00129 | ĩ |
iukcy; |
U+00456 | і |
iuml; |
U+000EF | ï |
jcirc; |
U+00135 | ĵ |
jcy; |
U+00439 | й |
jfr; |
U+1D527 | 𝔧 |
jmath; |
U+00237 | ȷ |
jopf; |
U+1D55B | 𝕛 |
jscr; |
U+1D4BF | 𝒿 |
jsercy; |
U+00458 | ј |
jukcy; |
U+00454 | є |
kappa; |
U+003BA | κ |
kappav; |
U+003F0 | ϰ |
kcedil; |
U+00137 | ķ |
kcy; |
U+0043A | к |
kfr; |
U+1D528 | 𝔨 |
kgreen; |
U+00138 | ĸ |
khcy; |
U+00445 | х |
kjcy; |
U+0045C | ќ |
kopf; |
U+1D55C | 𝕜 |
kscr; |
U+1D4C0 | 𝓀 |
lAarr; |
U+021DA | ⇚ |
lArr; |
U+021D0 | ⇐ |
lAtail; |
U+0291B | ⤛ |
lBarr; |
U+0290E | ⤎ |
lE; |
U+02266 | ≦ |
lEg; |
U+02A8B | ⪋ |
lHar; |
U+02962 | ⥢ |
lacute; |
U+0013A | ĺ |
laemptyv; |
U+029B4 | ⦴ |
lagran; |
U+02112 | ℒ |
lambda; |
U+003BB | λ |
lang; |
U+027E8 | ⟨ |
langd; |
U+02991 | ⦑ |
langle; |
U+027E8 | ⟨ |
lap; |
U+02A85 | ⪅ |
laquo; |
U+000AB | « |
larr; |
U+02190 | ← |
larrb; |
U+021E4 | ⇤ |
larrbfs; |
U+0291F | ⤟ |
larrfs; |
U+0291D | ⤝ |
larrhk; |
U+021A9 | ↩ |
larrlp; |
U+021AB | ↫ |
larrpl; |
U+02939 | ⤹ |
larrsim; |
U+02973 | ⥳ |
larrtl; |
U+021A2 | ↢ |
lat; |
U+02AAB | ⪫ |
latail; |
U+02919 | ⤙ |
late; |
U+02AAD | ⪭ |
lates; |
U+02AAD U+0FE00 | ⪭︀ |
lbarr; |
U+0290C | ⤌ |
lbbrk; |
U+02772 | ❲ |
lbrace; |
U+0007B | { |
lbrack; |
U+0005B | [ |
lbrke; |
U+0298B | ⦋ |
lbrksld; |
U+0298F | ⦏ |
lbrkslu; |
U+0298D | ⦍ |
lcaron; |
U+0013E | ľ |
lcedil; |
U+0013C | ļ |
lceil; |
U+02308 | ⌈ |
lcub; |
U+0007B | { |
lcy; |
U+0043B | л |
ldca; |
U+02936 | ⤶ |
ldquo; |
U+0201C | “ |
ldquor; |
U+0201E | „ |
ldrdhar; |
U+02967 | ⥧ |
ldrushar; |
U+0294B | ⥋ |
ldsh; |
U+021B2 | ↲ |
le; |
U+02264 | ≤ |
leftarrow; |
U+02190 | ← |
leftarrowtail; |
U+021A2 | ↢ |
leftharpoondown; |
U+021BD | ↽ |
leftharpoonup; |
U+021BC | ↼ |
leftleftarrows; |
U+021C7 | ⇇ |
leftrightarrow; |
U+02194 | ↔ |
leftrightarrows; |
U+021C6 | ⇆ |
leftrightharpoons; |
U+021CB | ⇋ |
leftrightsquigarrow; |
U+021AD | ↭ |
leftthreetimes; |
U+022CB | ⋋ |
leg; |
U+022DA | ⋚ |
leq; |
U+02264 | ≤ |
leqq; |
U+02266 | ≦ |
leqslant; |
U+02A7D | ⩽ |
les; |
U+02A7D | ⩽ |
lescc; |
U+02AA8 | ⪨ |
lesdot; |
U+02A7F | ⩿ |
lesdoto; |
U+02A81 | ⪁ |
lesdotor; |
U+02A83 | ⪃ |
lesg; |
U+022DA U+0FE00 | ⋚︀ |
lesges; |
U+02A93 | ⪓ |
lessapprox; |
U+02A85 | ⪅ |
lessdot; |
U+022D6 | ⋖ |
lesseqgtr; |
U+022DA | ⋚ |
lesseqqgtr; |
U+02A8B | ⪋ |
lessgtr; |
U+02276 | ≶ |
lesssim; |
U+02272 | ≲ |
lfisht; |
U+0297C | ⥼ |
lfloor; |
U+0230A | ⌊ |
lfr; |
U+1D529 | 𝔩 |
lg; |
U+02276 | ≶ |
lgE; |
U+02A91 | ⪑ |
lhard; |
U+021BD | ↽ |
lharu; |
U+021BC | ↼ |
lharul; |
U+0296A | ⥪ |
lhblk; |
U+02584 | ▄ |
ljcy; |
U+00459 | љ |
ll; |
U+0226A | ≪ |
llarr; |
U+021C7 | ⇇ |
llcorner; |
U+0231E | ⌞ |
llhard; |
U+0296B | ⥫ |
lltri; |
U+025FA | ◺ |
lmidot; |
U+00140 | ŀ |
lmoust; |
U+023B0 | ⎰ |
lmoustache; |
U+023B0 | ⎰ |
lnE; |
U+02268 | ≨ |
lnap; |
U+02A89 | ⪉ |
lnapprox; |
U+02A89 | ⪉ |
lne; |
U+02A87 | ⪇ |
lneq; |
U+02A87 | ⪇ |
lneqq; |
U+02268 | ≨ |
lnsim; |
U+022E6 | ⋦ |
loang; |
U+027EC | ⟬ |
loarr; |
U+021FD | ⇽ |
lobrk; |
U+027E6 | ⟦ |
longleftarrow; |
U+027F5 | ⟵ |
longleftrightarrow; |
U+027F7 | ⟷ |
longmapsto; |
U+027FC | ⟼ |
longrightarrow; |
U+027F6 | ⟶ |
looparrowleft; |
U+021AB | ↫ |
looparrowright; |
U+021AC | ↬ |
lopar; |
U+02985 | ⦅ |
lopf; |
U+1D55D | 𝕝 |
loplus; |
U+02A2D | ⨭ |
lotimes; |
U+02A34 | ⨴ |
lowast; |
U+02217 | ∗ |
lowbar; |
U+0005F | _ |
loz; |
U+025CA | ◊ |
lozenge; |
U+025CA | ◊ |
lozf; |
U+029EB | ⧫ |
lpar; |
U+00028 | ( |
lparlt; |
U+02993 | ⦓ |
lrarr; |
U+021C6 | ⇆ |
lrcorner; |
U+0231F | ⌟ |
lrhar; |
U+021CB | ⇋ |
lrhard; |
U+0296D | ⥭ |
lrm; |
U+0200E | |
lrtri; |
U+022BF | ⊿ |
lsaquo; |
U+02039 | ‹ |
lscr; |
U+1D4C1 | 𝓁 |
lsh; |
U+021B0 | ↰ |
lsim; |
U+02272 | ≲ |
lsime; |
U+02A8D | ⪍ |
lsimg; |
U+02A8F | ⪏ |
lsqb; |
U+0005B | [ |
lsquo; |
U+02018 | ‘ |
lsquor; |
U+0201A | ‚ |
lstrok; |
U+00142 | ł |
lt; |
U+0003C | < |
ltcc; |
U+02AA6 | ⪦ |
ltcir; |
U+02A79 | ⩹ |
ltdot; |
U+022D6 | ⋖ |
lthree; |
U+022CB | ⋋ |
ltimes; |
U+022C9 | ⋉ |
ltlarr; |
U+02976 | ⥶ |
ltquest; |
U+02A7B | ⩻ |
ltrPar; |
U+02996 | ⦖ |
ltri; |
U+025C3 | ◃ |
ltrie; |
U+022B4 | ⊴ |
ltrif; |
U+025C2 | ◂ |
lurdshar; |
U+0294A | ⥊ |
luruhar; |
U+02966 | ⥦ |
lvertneqq; |
U+02268 U+0FE00 | ≨︀ |
lvnE; |
U+02268 U+0FE00 | ≨︀ |
mDDot; |
U+0223A | ∺ |
macr; |
U+000AF | ¯ |
male; |
U+02642 | ♂ |
malt; |
U+02720 | ✠ |
maltese; |
U+02720 | ✠ |
map; |
U+021A6 | ↦ |
mapsto; |
U+021A6 | ↦ |
mapstodown; |
U+021A7 | ↧ |
mapstoleft; |
U+021A4 | ↤ |
mapstoup; |
U+021A5 | ↥ |
marker; |
U+025AE | ▮ |
mcomma; |
U+02A29 | ⨩ |
mcy; |
U+0043C | м |
mdash; |
U+02014 | — |
measuredangle; |
U+02221 | ∡ |
mfr; |
U+1D52A | 𝔪 |
mho; |
U+02127 | ℧ |
micro; |
U+000B5 | µ |
mid; |
U+02223 | ∣ |
midast; |
U+0002A | * |
midcir; |
U+02AF0 | ⫰ |
middot; |
U+000B7 | · |
minus; |
U+02212 | − |
minusb; |
U+0229F | ⊟ |
minusd; |
U+02238 | ∸ |
minusdu; |
U+02A2A | ⨪ |
mlcp; |
U+02ADB | ⫛ |
mldr; |
U+02026 | … |
mnplus; |
U+02213 | ∓ |
models; |
U+022A7 | ⊧ |
mopf; |
U+1D55E | 𝕞 |
mp; |
U+02213 | ∓ |
mscr; |
U+1D4C2 | 𝓂 |
mstpos; |
U+0223E | ∾ |
mu; |
U+003BC | μ |
multimap; |
U+022B8 | ⊸ |
mumap; |
U+022B8 | ⊸ |
nGg; |
U+022D9 U+00338 | ⋙̸ |
nGt; |
U+0226B U+020D2 | ≫⃒ |
nGtv; |
U+0226B U+00338 | ≫̸ |
nLeftarrow; |
U+021CD | ⇍ |
nLeftrightarrow; |
U+021CE | ⇎ |
nLl; |
U+022D8 U+00338 | ⋘̸ |
nLt; |
U+0226A U+020D2 | ≪⃒ |
nLtv; |
U+0226A U+00338 | ≪̸ |
nRightarrow; |
U+021CF | ⇏ |
nVDash; |
U+022AF | ⊯ |
nVdash; |
U+022AE | ⊮ |
nabla; |
U+02207 | ∇ |
nacute; |
U+00144 | ń |
nang; |
U+02220 U+020D2 | ∠⃒ |
nap; |
U+02249 | ≉ |
napE; |
U+02A70 U+00338 | ⩰̸ |
napid; |
U+0224B U+00338 | ≋̸ |
napos; |
U+00149 | ʼn |
napprox; |
U+02249 | ≉ |
natur; |
U+0266E | ♮ |
natural; |
U+0266E | ♮ |
naturals; |
U+02115 | ℕ |
nbsp; |
U+000A0 | |
nbump; |
U+0224E U+00338 | ≎̸ |
nbumpe; |
U+0224F U+00338 | ≏̸ |
ncap; |
U+02A43 | ⩃ |
ncaron; |
U+00148 | ň |
ncedil; |
U+00146 | ņ |
ncong; |
U+02247 | ≇ |
ncongdot; |
U+02A6D U+00338 | ⩭̸ |
ncup; |
U+02A42 | ⩂ |
ncy; |
U+0043D | н |
ndash; |
U+02013 | – |
ne; |
U+02260 | ≠ |
neArr; |
U+021D7 | ⇗ |
nearhk; |
U+02924 | ⤤ |
nearr; |
U+02197 | ↗ |
nearrow; |
U+02197 | ↗ |
nedot; |
U+02250 U+00338 | ≐̸ |
nequiv; |
U+02262 | ≢ |
nesear; |
U+02928 | ⤨ |
nesim; |
U+02242 U+00338 | ≂̸ |
nexist; |
U+02204 | ∄ |
nexists; |
U+02204 | ∄ |
nfr; |
U+1D52B | 𝔫 |
ngE; |
U+02267 U+00338 | ≧̸ |
nge; |
U+02271 | ≱ |
ngeq; |
U+02271 | ≱ |
ngeqq; |
U+02267 U+00338 | ≧̸ |
ngeqslant; |
U+02A7E U+00338 | ⩾̸ |
nges; |
U+02A7E U+00338 | ⩾̸ |
ngsim; |
U+02275 | ≵ |
ngt; |
U+0226F | ≯ |
ngtr; |
U+0226F | ≯ |
nhArr; |
U+021CE | ⇎ |
nharr; |
U+021AE | ↮ |
nhpar; |
U+02AF2 | ⫲ |
ni; |
U+0220B | ∋ |
nis; |
U+022FC | ⋼ |
nisd; |
U+022FA | ⋺ |
niv; |
U+0220B | ∋ |
njcy; |
U+0045A | њ |
nlArr; |
U+021CD | ⇍ |
nlE; |
U+02266 U+00338 | ≦̸ |
nlarr; |
U+0219A | ↚ |
nldr; |
U+02025 | ‥ |
nle; |
U+02270 | ≰ |
nleftarrow; |
U+0219A | ↚ |
nleftrightarrow; |
U+021AE | ↮ |
nleq; |
U+02270 | ≰ |
nleqq; |
U+02266 U+00338 | ≦̸ |
nleqslant; |
U+02A7D U+00338 | ⩽̸ |
nles; |
U+02A7D U+00338 | ⩽̸ |
nless; |
U+0226E | ≮ |
nlsim; |
U+02274 | ≴ |
nlt; |
U+0226E | ≮ |
nltri; |
U+022EA | ⋪ |
nltrie; |
U+022EC | ⋬ |
nmid; |
U+02224 | ∤ |
nopf; |
U+1D55F | 𝕟 |
not; |
U+000AC | ¬ |
notin; |
U+02209 | ∉ |
notinE; |
U+022F9 U+00338 | ⋹̸ |
notindot; |
U+022F5 U+00338 | ⋵̸ |
notinva; |
U+02209 | ∉ |
notinvb; |
U+022F7 | ⋷ |
notinvc; |
U+022F6 | ⋶ |
notni; |
U+0220C | ∌ |
notniva; |
U+0220C | ∌ |
notnivb; |
U+022FE | ⋾ |
notnivc; |
U+022FD | ⋽ |
npar; |
U+02226 | ∦ |
nparallel; |
U+02226 | ∦ |
nparsl; |
U+02AFD U+020E5 | ⫽⃥ |
npart; |
U+02202 U+00338 | ∂̸ |
npolint; |
U+02A14 | ⨔ |
npr; |
U+02280 | ⊀ |
nprcue; |
U+022E0 | ⋠ |
npre; |
U+02AAF U+00338 | ⪯̸ |
nprec; |
U+02280 | ⊀ |
npreceq; |
U+02AAF U+00338 | ⪯̸ |
nrArr; |
U+021CF | ⇏ |
nrarr; |
U+0219B | ↛ |
nrarrc; |
U+02933 U+00338 | ⤳̸ |
nrarrw; |
U+0219D U+00338 | ↝̸ |
nrightarrow; |
U+0219B | ↛ |
nrtri; |
U+022EB | ⋫ |
nrtrie; |
U+022ED | ⋭ |
nsc; |
U+02281 | ⊁ |
nsccue; |
U+022E1 | ⋡ |
nsce; |
U+02AB0 U+00338 | ⪰̸ |
nscr; |
U+1D4C3 | 𝓃 |
nshortmid; |
U+02224 | ∤ |
nshortparallel; |
U+02226 | ∦ |
nsim; |
U+02241 | ≁ |
nsime; |
U+02244 | ≄ |
nsimeq; |
U+02244 | ≄ |
nsmid; |
U+02224 | ∤ |
nspar; |
U+02226 | ∦ |
nsqsube; |
U+022E2 | ⋢ |
nsqsupe; |
U+022E3 | ⋣ |
nsub; |
U+02284 | ⊄ |
nsubE; |
U+02AC5 U+00338 | ⫅̸ |
nsube; |
U+02288 | ⊈ |
nsubset; |
U+02282 U+020D2 | ⊂⃒ |
nsubseteq; |
U+02288 | ⊈ |
nsubseteqq; |
U+02AC5 U+00338 | ⫅̸ |
nsucc; |
U+02281 | ⊁ |
nsucceq; |
U+02AB0 U+00338 | ⪰̸ |
nsup; |
U+02285 | ⊅ |
nsupE; |
U+02AC6 U+00338 | ⫆̸ |
nsupe; |
U+02289 | ⊉ |
nsupset; |
U+02283 U+020D2 | ⊃⃒ |
nsupseteq; |
U+02289 | ⊉ |
nsupseteqq; |
U+02AC6 U+00338 | ⫆̸ |
ntgl; |
U+02279 | ≹ |
ntilde; |
U+000F1 | ñ |
ntlg; |
U+02278 | ≸ |
ntriangleleft; |
U+022EA | ⋪ |
ntrianglelefteq; |
U+022EC | ⋬ |
ntriangleright; |
U+022EB | ⋫ |
ntrianglerighteq; |
U+022ED | ⋭ |
nu; |
U+003BD | ν |
num; |
U+00023 | # |
numero; |
U+02116 | № |
numsp; |
U+02007 | |
nvDash; |
U+022AD | ⊭ |
nvHarr; |
U+02904 | ⤄ |
nvap; |
U+0224D U+020D2 | ≍⃒ |
nvdash; |
U+022AC | ⊬ |
nvge; |
U+02265 U+020D2 | ≥⃒ |
nvgt; |
U+0003E U+020D2 | >⃒ |
nvinfin; |
U+029DE | ⧞ |
nvlArr; |
U+02902 | ⤂ |
nvle; |
U+02264 U+020D2 | ≤⃒ |
nvlt; |
U+0003C U+020D2 | <⃒ |
nvltrie; |
U+022B4 U+020D2 | ⊴⃒ |
nvrArr; |
U+02903 | ⤃ |
nvrtrie; |
U+022B5 U+020D2 | ⊵⃒ |
nvsim; |
U+0223C U+020D2 | ∼⃒ |
nwArr; |
U+021D6 | ⇖ |
nwarhk; |
U+02923 | ⤣ |
nwarr; |
U+02196 | ↖ |
nwarrow; |
U+02196 | ↖ |
nwnear; |
U+02927 | ⤧ |
oS; |
U+024C8 | Ⓢ |
oacute; |
U+000F3 | ó |
oast; |
U+0229B | ⊛ |
ocir; |
U+0229A | ⊚ |
ocirc; |
U+000F4 | ô |
ocy; |
U+0043E | о |
odash; |
U+0229D | ⊝ |
odblac; |
U+00151 | ő |
odiv; |
U+02A38 | ⨸ |
odot; |
U+02299 | ⊙ |
odsold; |
U+029BC | ⦼ |
oelig; |
U+00153 | œ |
ofcir; |
U+029BF | ⦿ |
ofr; |
U+1D52C | 𝔬 |
ogon; |
U+002DB | ˛ |
ograve; |
U+000F2 | ò |
ogt; |
U+029C1 | ⧁ |
ohbar; |
U+029B5 | ⦵ |
ohm; |
U+003A9 | Ω |
oint; |
U+0222E | ∮ |
olarr; |
U+021BA | ↺ |
olcir; |
U+029BE | ⦾ |
olcross; |
U+029BB | ⦻ |
oline; |
U+0203E | ‾ |
olt; |
U+029C0 | ⧀ |
omacr; |
U+0014D | ō |
omega; |
U+003C9 | ω |
omicron; |
U+003BF | ο |
omid; |
U+029B6 | ⦶ |
ominus; |
U+02296 | ⊖ |
oopf; |
U+1D560 | 𝕠 |
opar; |
U+029B7 | ⦷ |
operp; |
U+029B9 | ⦹ |
oplus; |
U+02295 | ⊕ |
or; |
U+02228 | ∨ |
orarr; |
U+021BB | ↻ |
ord; |
U+02A5D | ⩝ |
order; |
U+02134 | ℴ |
orderof; |
U+02134 | ℴ |
ordf; |
U+000AA | ª |
ordm; |
U+000BA | º |
origof; |
U+022B6 | ⊶ |
oror; |
U+02A56 | ⩖ |
orslope; |
U+02A57 | ⩗ |
orv; |
U+02A5B | ⩛ |
oscr; |
U+02134 | ℴ |
oslash; |
U+000F8 | ø |
osol; |
U+02298 | ⊘ |
otilde; |
U+000F5 | õ |
otimes; |
U+02297 | ⊗ |
otimesas; |
U+02A36 | ⨶ |
ouml; |
U+000F6 | ö |
ovbar; |
U+0233D | ⌽ |
par; |
U+02225 | ∥ |
para; |
U+000B6 | ¶ |
parallel; |
U+02225 | ∥ |
parsim; |
U+02AF3 | ⫳ |
parsl; |
U+02AFD | ⫽ |
part; |
U+02202 | ∂ |
pcy; |
U+0043F | п |
percnt; |
U+00025 | % |
period; |
U+0002E | . |
permil; |
U+02030 | ‰ |
perp; |
U+022A5 | ⊥ |
pertenk; |
U+02031 | ‱ |
pfr; |
U+1D52D | 𝔭 |
phi; |
U+003C6 | φ |
phiv; |
U+003D5 | ϕ |
phmmat; |
U+02133 | ℳ |
phone; |
U+0260E | ☎ |
pi; |
U+003C0 | π |
pitchfork; |
U+022D4 | ⋔ |
piv; |
U+003D6 | ϖ |
planck; |
U+0210F | ℏ |
planckh; |
U+0210E | ℎ |
plankv; |
U+0210F | ℏ |
plus; |
U+0002B | + |
plusacir; |
U+02A23 | ⨣ |
plusb; |
U+0229E | ⊞ |
pluscir; |
U+02A22 | ⨢ |
plusdo; |
U+02214 | ∔ |
plusdu; |
U+02A25 | ⨥ |
pluse; |
U+02A72 | ⩲ |
plusmn; |
U+000B1 | ± |
plussim; |
U+02A26 | ⨦ |
plustwo; |
U+02A27 | ⨧ |
pm; |
U+000B1 | ± |
pointint; |
U+02A15 | ⨕ |
popf; |
U+1D561 | 𝕡 |
pound; |
U+000A3 | £ |
pr; |
U+0227A | ≺ |
prE; |
U+02AB3 | ⪳ |
prap; |
U+02AB7 | ⪷ |
prcue; |
U+0227C | ≼ |
pre; |
U+02AAF | ⪯ |
prec; |
U+0227A | ≺ |
precapprox; |
U+02AB7 | ⪷ |
preccurlyeq; |
U+0227C | ≼ |
preceq; |
U+02AAF | ⪯ |
precnapprox; |
U+02AB9 | ⪹ |
precneqq; |
U+02AB5 | ⪵ |
precnsim; |
U+022E8 | ⋨ |
precsim; |
U+0227E | ≾ |
prime; |
U+02032 | ′ |
primes; |
U+02119 | ℙ |
prnE; |
U+02AB5 | ⪵ |
prnap; |
U+02AB9 | ⪹ |
prnsim; |
U+022E8 | ⋨ |
prod; |
U+0220F | ∏ |
profalar; |
U+0232E | ⌮ |
profline; |
U+02312 | ⌒ |
profsurf; |
U+02313 | ⌓ |
prop; |
U+0221D | ∝ |
propto; |
U+0221D | ∝ |
prsim; |
U+0227E | ≾ |
prurel; |
U+022B0 | ⊰ |
pscr; |
U+1D4C5 | 𝓅 |
psi; |
U+003C8 | ψ |
puncsp; |
U+02008 | |
qfr; |
U+1D52E | 𝔮 |
qint; |
U+02A0C | ⨌ |
qopf; |
U+1D562 | 𝕢 |
qprime; |
U+02057 | ⁗ |
qscr; |
U+1D4C6 | 𝓆 |
quaternions; |
U+0210D | ℍ |
quatint; |
U+02A16 | ⨖ |
quest; |
U+0003F | ? |
questeq; |
U+0225F | ≟ |
quot; |
U+00022 | " |
rAarr; |
U+021DB | ⇛ |
rArr; |
U+021D2 | ⇒ |
rAtail; |
U+0291C | ⤜ |
rBarr; |
U+0290F | ⤏ |
rHar; |
U+02964 | ⥤ |
race; |
U+0223D U+00331 | ∽̱ |
racute; |
U+00155 | ŕ |
radic; |
U+0221A | √ |
raemptyv; |
U+029B3 | ⦳ |
rang; |
U+027E9 | ⟩ |
rangd; |
U+02992 | ⦒ |
range; |
U+029A5 | ⦥ |
rangle; |
U+027E9 | ⟩ |
raquo; |
U+000BB | » |
rarr; |
U+02192 | → |
rarrap; |
U+02975 | ⥵ |
rarrb; |
U+021E5 | ⇥ |
rarrbfs; |
U+02920 | ⤠ |
rarrc; |
U+02933 | ⤳ |
rarrfs; |
U+0291E | ⤞ |
rarrhk; |
U+021AA | ↪ |
rarrlp; |
U+021AC | ↬ |
rarrpl; |
U+02945 | ⥅ |
rarrsim; |
U+02974 | ⥴ |
rarrtl; |
U+021A3 | ↣ |
rarrw; |
U+0219D | ↝ |
ratail; |
U+0291A | ⤚ |
ratio; |
U+02236 | ∶ |
rationals; |
U+0211A | ℚ |
rbarr; |
U+0290D | ⤍ |
rbbrk; |
U+02773 | ❳ |
rbrace; |
U+0007D | } |
rbrack; |
U+0005D | ] |
rbrke; |
U+0298C | ⦌ |
rbrksld; |
U+0298E | ⦎ |
rbrkslu; |
U+02990 | ⦐ |
rcaron; |
U+00159 | ř |
rcedil; |
U+00157 | ŗ |
rceil; |
U+02309 | ⌉ |
rcub; |
U+0007D | } |
rcy; |
U+00440 | р |
rdca; |
U+02937 | ⤷ |
rdldhar; |
U+02969 | ⥩ |
rdquo; |
U+0201D | ” |
rdquor; |
U+0201D | ” |
rdsh; |
U+021B3 | ↳ |
real; |
U+0211C | ℜ |
realine; |
U+0211B | ℛ |
realpart; |
U+0211C | ℜ |
reals; |
U+0211D | ℝ |
rect; |
U+025AD | ▭ |
reg; |
U+000AE | ® |
rfisht; |
U+0297D | ⥽ |
rfloor; |
U+0230B | ⌋ |
rfr; |
U+1D52F | 𝔯 |
rhard; |
U+021C1 | ⇁ |
rharu; |
U+021C0 | ⇀ |
rharul; |
U+0296C | ⥬ |
rho; |
U+003C1 | ρ |
rhov; |
U+003F1 | ϱ |
rightarrow; |
U+02192 | → |
rightarrowtail; |
U+021A3 | ↣ |
rightharpoondown; |
U+021C1 | ⇁ |
rightharpoonup; |
U+021C0 | ⇀ |
rightleftarrows; |
U+021C4 | ⇄ |
rightleftharpoons; |
U+021CC | ⇌ |
rightrightarrows; |
U+021C9 | ⇉ |
rightsquigarrow; |
U+0219D | ↝ |
rightthreetimes; |
U+022CC | ⋌ |
ring; |
U+002DA | ˚ |
risingdotseq; |
U+02253 | ≓ |
rlarr; |
U+021C4 | ⇄ |
rlhar; |
U+021CC | ⇌ |
rlm; |
U+0200F | |
rmoust; |
U+023B1 | ⎱ |
rmoustache; |
U+023B1 | ⎱ |
rnmid; |
U+02AEE | ⫮ |
roang; |
U+027ED | ⟭ |
roarr; |
U+021FE | ⇾ |
robrk; |
U+027E7 | ⟧ |
ropar; |
U+02986 | ⦆ |
ropf; |
U+1D563 | 𝕣 |
roplus; |
U+02A2E | ⨮ |
rotimes; |
U+02A35 | ⨵ |
rpar; |
U+00029 | ) |
rpargt; |
U+02994 | ⦔ |
rppolint; |
U+02A12 | ⨒ |
rrarr; |
U+021C9 | ⇉ |
rsaquo; |
U+0203A | › |
rscr; |
U+1D4C7 | 𝓇 |
rsh; |
U+021B1 | ↱ |
rsqb; |
U+0005D | ] |
rsquo; |
U+02019 | ’ |
rsquor; |
U+02019 | ’ |
rthree; |
U+022CC | ⋌ |
rtimes; |
U+022CA | ⋊ |
rtri; |
U+025B9 | ▹ |
rtrie; |
U+022B5 | ⊵ |
rtrif; |
U+025B8 | ▸ |
rtriltri; |
U+029CE | ⧎ |
ruluhar; |
U+02968 | ⥨ |
rx; |
U+0211E | ℞ |
sacute; |
U+0015B | ś |
sbquo; |
U+0201A | ‚ |
sc; |
U+0227B | ≻ |
scE; |
U+02AB4 | ⪴ |
scap; |
U+02AB8 | ⪸ |
scaron; |
U+00161 | š |
sccue; |
U+0227D | ≽ |
sce; |
U+02AB0 | ⪰ |
scedil; |
U+0015F | ş |
scirc; |
U+0015D | ŝ |
scnE; |
U+02AB6 | ⪶ |
scnap; |
U+02ABA | ⪺ |
scnsim; |
U+022E9 | ⋩ |
scpolint; |
U+02A13 | ⨓ |
scsim; |
U+0227F | ≿ |
scy; |
U+00441 | с |
sdot; |
U+022C5 | ⋅ |
sdotb; |
U+022A1 | ⊡ |
sdote; |
U+02A66 | ⩦ |
seArr; |
U+021D8 | ⇘ |
searhk; |
U+02925 | ⤥ |
searr; |
U+02198 | ↘ |
searrow; |
U+02198 | ↘ |
sect; |
U+000A7 | § |
semi; |
U+0003B | ; |
seswar; |
U+02929 | ⤩ |
setminus; |
U+02216 | ∖ |
setmn; |
U+02216 | ∖ |
sext; |
U+02736 | ✶ |
sfr; |
U+1D530 | 𝔰 |
sfrown; |
U+02322 | ⌢ |
sharp; |
U+0266F | ♯ |
shchcy; |
U+00449 | щ |
shcy; |
U+00448 | ш |
shortmid; |
U+02223 | ∣ |
shortparallel; |
U+02225 | ∥ |
shy; |
U+000AD | |
sigma; |
U+003C3 | σ |
sigmaf; |
U+003C2 | ς |
sigmav; |
U+003C2 | ς |
sim; |
U+0223C | ∼ |
simdot; |
U+02A6A | ⩪ |
sime; |
U+02243 | ≃ |
simeq; |
U+02243 | ≃ |
simg; |
U+02A9E | ⪞ |
simgE; |
U+02AA0 | ⪠ |
siml; |
U+02A9D | ⪝ |
simlE; |
U+02A9F | ⪟ |
simne; |
U+02246 | ≆ |
simplus; |
U+02A24 | ⨤ |
simrarr; |
U+02972 | ⥲ |
slarr; |
U+02190 | ← |
smallsetminus; |
U+02216 | ∖ |
smashp; |
U+02A33 | ⨳ |
smeparsl; |
U+029E4 | ⧤ |
smid; |
U+02223 | ∣ |
smile; |
U+02323 | ⌣ |
smt; |
U+02AAA | ⪪ |
smte; |
U+02AAC | ⪬ |
smtes; |
U+02AAC U+0FE00 | ⪬︀ |
softcy; |
U+0044C | ь |
sol; |
U+0002F | / |
solb; |
U+029C4 | ⧄ |
solbar; |
U+0233F | ⌿ |
sopf; |
U+1D564 | 𝕤 |
spades; |
U+02660 | ♠ |
spadesuit; |
U+02660 | ♠ |
spar; |
U+02225 | ∥ |
sqcap; |
U+02293 | ⊓ |
sqcaps; |
U+02293 U+0FE00 | ⊓︀ |
sqcup; |
U+02294 | ⊔ |
sqcups; |
U+02294 U+0FE00 | ⊔︀ |
sqsub; |
U+0228F | ⊏ |
sqsube; |
U+02291 | ⊑ |
sqsubset; |
U+0228F | ⊏ |
sqsubseteq; |
U+02291 | ⊑ |
sqsup; |
U+02290 | ⊐ |
sqsupe; |
U+02292 | ⊒ |
sqsupset; |
U+02290 | ⊐ |
sqsupseteq; |
U+02292 | ⊒ |
squ; |
U+025A1 | □ |
square; |
U+025A1 | □ |
squarf; |
U+025AA | ▪ |
squf; |
U+025AA | ▪ |
srarr; |
U+02192 | → |
sscr; |
U+1D4C8 | 𝓈 |
ssetmn; |
U+02216 | ∖ |
ssmile; |
U+02323 | ⌣ |
sstarf; |
U+022C6 | ⋆ |
star; |
U+02606 | ☆ |
starf; |
U+02605 | ★ |
straightepsilon; |
U+003F5 | ϵ |
straightphi; |
U+003D5 | ϕ |
strns; |
U+000AF | ¯ |
sub; |
U+02282 | ⊂ |
subE; |
U+02AC5 | ⫅ |
subdot; |
U+02ABD | ⪽ |
sube; |
U+02286 | ⊆ |
subedot; |
U+02AC3 | ⫃ |
submult; |
U+02AC1 | ⫁ |
subnE; |
U+02ACB | ⫋ |
subne; |
U+0228A | ⊊ |
subplus; |
U+02ABF | ⪿ |
subrarr; |
U+02979 | ⥹ |
subset; |
U+02282 | ⊂ |
subseteq; |
U+02286 | ⊆ |
subseteqq; |
U+02AC5 | ⫅ |
subsetneq; |
U+0228A | ⊊ |
subsetneqq; |
U+02ACB | ⫋ |
subsim; |
U+02AC7 | ⫇ |
subsub; |
U+02AD5 | ⫕ |
subsup; |
U+02AD3 | ⫓ |
succ; |
U+0227B | ≻ |
succapprox; |
U+02AB8 | ⪸ |
succcurlyeq; |
U+0227D | ≽ |
succeq; |
U+02AB0 | ⪰ |
succnapprox; |
U+02ABA | ⪺ |
succneqq; |
U+02AB6 | ⪶ |
succnsim; |
U+022E9 | ⋩ |
succsim; |
U+0227F | ≿ |
sum; |
U+02211 | ∑ |
sung; |
U+0266A | ♪ |
sup; |
U+02283 | ⊃ |
sup1; |
U+000B9 | ¹ |
sup2; |
U+000B2 | ² |
sup3; |
U+000B3 | ³ |
supE; |
U+02AC6 | ⫆ |
supdot; |
U+02ABE | ⪾ |
supdsub; |
U+02AD8 | ⫘ |
supe; |
U+02287 | ⊇ |
supedot; |
U+02AC4 | ⫄ |
suphsol; |
U+027C9 | ⟉ |
suphsub; |
U+02AD7 | ⫗ |
suplarr; |
U+0297B | ⥻ |
supmult; |
U+02AC2 | ⫂ |
supnE; |
U+02ACC | ⫌ |
supne; |
U+0228B | ⊋ |
supplus; |
U+02AC0 | ⫀ |
supset; |
U+02283 | ⊃ |
supseteq; |
U+02287 | ⊇ |
supseteqq; |
U+02AC6 | ⫆ |
supsetneq; |
U+0228B | ⊋ |
supsetneqq; |
U+02ACC | ⫌ |
supsim; |
U+02AC8 | ⫈ |
supsub; |
U+02AD4 | ⫔ |
supsup; |
U+02AD6 | ⫖ |
swArr; |
U+021D9 | ⇙ |
swarhk; |
U+02926 | ⤦ |
swarr; |
U+02199 | ↙ |
swarrow; |
U+02199 | ↙ |
swnwar; |
U+0292A | ⤪ |
szlig; |
U+000DF | ß |
target; |
U+02316 | ⌖ |
tau; |
U+003C4 | τ |
tbrk; |
U+023B4 | ⎴ |
tcaron; |
U+00165 | ť |
tcedil; |
U+00163 | ţ |
tcy; |
U+00442 | т |
tdot; |
U+020DB | ◌⃛ |
telrec; |
U+02315 | ⌕ |
tfr; |
U+1D531 | 𝔱 |
there4; |
U+02234 | ∴ |
therefore; |
U+02234 | ∴ |
theta; |
U+003B8 | θ |
thetasym; |
U+003D1 | ϑ |
thetav; |
U+003D1 | ϑ |
thickapprox; |
U+02248 | ≈ |
thicksim; |
U+0223C | ∼ |
thinsp; |
U+02009 | |
thkap; |
U+02248 | ≈ |
thksim; |
U+0223C | ∼ |
thorn; |
U+000FE | þ |
tilde; |
U+002DC | ˜ |
times; |
U+000D7 | × |
timesb; |
U+022A0 | ⊠ |
timesbar; |
U+02A31 | ⨱ |
timesd; |
U+02A30 | ⨰ |
tint; |
U+0222D | ∭ |
toea; |
U+02928 | ⤨ |
top; |
U+022A4 | ⊤ |
topbot; |
U+02336 | ⌶ |
topcir; |
U+02AF1 | ⫱ |
topf; |
U+1D565 | 𝕥 |
topfork; |
U+02ADA | ⫚ |
tosa; |
U+02929 | ⤩ |
tprime; |
U+02034 | ‴ |
trade; |
U+02122 | ™ |
triangle; |
U+025B5 | ▵ |
triangledown; |
U+025BF | ▿ |
triangleleft; |
U+025C3 | ◃ |
trianglelefteq; |
U+022B4 | ⊴ |
triangleq; |
U+0225C | ≜ |
triangleright; |
U+025B9 | ▹ |
trianglerighteq; |
U+022B5 | ⊵ |
tridot; |
U+025EC | ◬ |
trie; |
U+0225C | ≜ |
triminus; |
U+02A3A | ⨺ |
triplus; |
U+02A39 | ⨹ |
trisb; |
U+029CD | ⧍ |
tritime; |
U+02A3B | ⨻ |
trpezium; |
U+023E2 | ⏢ |
tscr; |
U+1D4C9 | 𝓉 |
tscy; |
U+00446 | ц |
tshcy; |
U+0045B | ћ |
tstrok; |
U+00167 | ŧ |
twixt; |
U+0226C | ≬ |
twoheadleftarrow; |
U+0219E | ↞ |
twoheadrightarrow; |
U+021A0 | ↠ |
uArr; |
U+021D1 | ⇑ |
uHar; |
U+02963 | ⥣ |
uacute; |
U+000FA | ú |
uarr; |
U+02191 | ↑ |
ubrcy; |
U+0045E | ў |
ubreve; |
U+0016D | ŭ |
ucirc; |
U+000FB | û |
ucy; |
U+00443 | у |
udarr; |
U+021C5 | ⇅ |
udblac; |
U+00171 | ű |
udhar; |
U+0296E | ⥮ |
ufisht; |
U+0297E | ⥾ |
ufr; |
U+1D532 | 𝔲 |
ugrave; |
U+000F9 | ù |
uharl; |
U+021BF | ↿ |
uharr; |
U+021BE | ↾ |
uhblk; |
U+02580 | ▀ |
ulcorn; |
U+0231C | ⌜ |
ulcorner; |
U+0231C | ⌜ |
ulcrop; |
U+0230F | ⌏ |
ultri; |
U+025F8 | ◸ |
umacr; |
U+0016B | ū |
uml; |
U+000A8 | ¨ |
uogon; |
U+00173 | ų |
uopf; |
U+1D566 | 𝕦 |
uparrow; |
U+02191 | ↑ |
updownarrow; |
U+02195 | ↕ |
upharpoonleft; |
U+021BF | ↿ |
upharpoonright; |
U+021BE | ↾ |
uplus; |
U+0228E | ⊎ |
upsi; |
U+003C5 | υ |
upsih; |
U+003D2 | ϒ |
upsilon; |
U+003C5 | υ |
upuparrows; |
U+021C8 | ⇈ |
urcorn; |
U+0231D | ⌝ |
urcorner; |
U+0231D | ⌝ |
urcrop; |
U+0230E | ⌎ |
uring; |
U+0016F | ů |
urtri; |
U+025F9 | ◹ |
uscr; |
U+1D4CA | 𝓊 |
utdot; |
U+022F0 | ⋰ |
utilde; |
U+00169 | ũ |
utri; |
U+025B5 | ▵ |
utrif; |
U+025B4 | ▴ |
uuarr; |
U+021C8 | ⇈ |
uuml; |
U+000FC | ü |
uwangle; |
U+029A7 | ⦧ |
vArr; |
U+021D5 | ⇕ |
vBar; |
U+02AE8 | ⫨ |
vBarv; |
U+02AE9 | ⫩ |
vDash; |
U+022A8 | ⊨ |
vangrt; |
U+0299C | ⦜ |
varepsilon; |
U+003F5 | ϵ |
varkappa; |
U+003F0 | ϰ |
varnothing; |
U+02205 | ∅ |
varphi; |
U+003D5 | ϕ |
varpi; |
U+003D6 | ϖ |
varpropto; |
U+0221D | ∝ |
varr; |
U+02195 | ↕ |
varrho; |
U+003F1 | ϱ |
varsigma; |
U+003C2 | ς |
varsubsetneq; |
U+0228A U+0FE00 | ⊊︀ |
varsubsetneqq; |
U+02ACB U+0FE00 | ⫋︀ |
varsupsetneq; |
U+0228B U+0FE00 | ⊋︀ |
varsupsetneqq; |
U+02ACC U+0FE00 | ⫌︀ |
vartheta; |
U+003D1 | ϑ |
vartriangleleft; |
U+022B2 | ⊲ |
vartriangleright; |
U+022B3 | ⊳ |
vcy; |
U+00432 | в |
vdash; |
U+022A2 | ⊢ |
vee; |
U+02228 | ∨ |
veebar; |
U+022BB | ⊻ |
veeeq; |
U+0225A | ≚ |
vellip; |
U+022EE | ⋮ |
verbar; |
U+0007C | | |
vert; |
U+0007C | | |
vfr; |
U+1D533 | 𝔳 |
vltri; |
U+022B2 | ⊲ |
vnsub; |
U+02282 U+020D2 | ⊂⃒ |
vnsup; |
U+02283 U+020D2 | ⊃⃒ |
vopf; |
U+1D567 | 𝕧 |
vprop; |
U+0221D | ∝ |
vrtri; |
U+022B3 | ⊳ |
vscr; |
U+1D4CB | 𝓋 |
vsubnE; |
U+02ACB U+0FE00 | ⫋︀ |
vsubne; |
U+0228A U+0FE00 | ⊊︀ |
vsupnE; |
U+02ACC U+0FE00 | ⫌︀ |
vsupne; |
U+0228B U+0FE00 | ⊋︀ |
vzigzag; |
U+0299A | ⦚ |
wcirc; |
U+00175 | ŵ |
wedbar; |
U+02A5F | ⩟ |
wedge; |
U+02227 | ∧ |
wedgeq; |
U+02259 | ≙ |
weierp; |
U+02118 | ℘ |
wfr; |
U+1D534 | 𝔴 |
wopf; |
U+1D568 | 𝕨 |
wp; |
U+02118 | ℘ |
wr; |
U+02240 | ≀ |
wreath; |
U+02240 | ≀ |
wscr; |
U+1D4CC | 𝓌 |
xcap; |
U+022C2 | ⋂ |
xcirc; |
U+025EF | ◯ |
xcup; |
U+022C3 | ⋃ |
xdtri; |
U+025BD | ▽ |
xfr; |
U+1D535 | 𝔵 |
xhArr; |
U+027FA | ⟺ |
xharr; |
U+027F7 | ⟷ |
xi; |
U+003BE | ξ |
xlArr; |
U+027F8 | ⟸ |
xlarr; |
U+027F5 | ⟵ |
xmap; |
U+027FC | ⟼ |
xnis; |
U+022FB | ⋻ |
xodot; |
U+02A00 | ⨀ |
xopf; |
U+1D569 | 𝕩 |
xoplus; |
U+02A01 | ⨁ |
xotime; |
U+02A02 | ⨂ |
xrArr; |
U+027F9 | ⟹ |
xrarr; |
U+027F6 | ⟶ |
xscr; |
U+1D4CD | 𝓍 |
xsqcup; |
U+02A06 | ⨆ |
xuplus; |
U+02A04 | ⨄ |
xutri; |
U+025B3 | △ |
xvee; |
U+022C1 | ⋁ |
xwedge; |
U+022C0 | ⋀ |
yacute; |
U+000FD | ý |
yacy; |
U+0044F | я |
ycirc; |
U+00177 | ŷ |
ycy; |
U+0044B | ы |
yen; |
U+000A5 | ¥ |
yfr; |
U+1D536 | 𝔶 |
yicy; |
U+00457 | ї |
yopf; |
U+1D56A | 𝕪 |
yscr; |
U+1D4CE | 𝓎 |
yucy; |
U+0044E | ю |
yuml; |
U+000FF | ÿ |
zacute; |
U+0017A | ź |
zcaron; |
U+0017E | ž |
zcy; |
U+00437 | з |
zdot; |
U+0017C | ż |
zeetrf; |
U+02128 | ℨ |
zeta; |
U+003B6 | ζ |
zfr; |
U+1D537 | 𝔷 |
zhcy; |
U+00436 | ж |
zigrarr; |
U+021DD | ⇝ |
zopf; |
U+1D56B | 𝕫 |
zscr; |
U+1D4CF | 𝓏 |
zwj; |
U+0200D | |
zwnj; |
U+0200C | |
The glyphs displayed above are non-normative. Refer to the Unicode specifications for formal definitions of the characters listed above.
This section only describes the rules for XML resources. Rules for text/html
resources are discussed in the section above entitled "The HTML syntax".
The syntax for using HTML with XML, whether in XHTML documents or embedded in other XML documents, is defined in the XML and Namespaces in XML specifications. [XML] [XMLNS]
This specification does not define any syntax-level requirements beyond those defined for XML proper.
XML documents may contain a DOCTYPE
if desired, but this is not required to conform to this specification. This specification does not define a public or system identifier, nor provide a format DTD.
According to the XML specification, XML processors are not guaranteed to process the external DTD subset referenced in the DOCTYPE. This means, for example, that using entity references for characters in XHTML documents is unsafe if they are defined in an external file (except for <
, >
, &
, "
and '
).
Features listed in this section will trigger warnings in conformance checkers.
Authors should not specify a border
attribute on an img
element. If the attribute is present, its value must be the string "0
". CSS should be used instead.
Authors should not specify a language
attribute on a script
element. If the attribute is present, its value must be an ASCII case-insensitive match for the string "JavaScript
" and either the type
attribute must be omitted or its value must be an ASCII case-insensitive match for the string "text/javascript
". The attribute should be entirely omitted instead (with the value "JavaScript
", it has no effect), or replaced with use of the type
attribute.
Authors should not specify the name
attribute on a
elements. If the attribute is present, its value must not be the empty string and must neither be equal to the value of any of the IDs in the element's home subtree other than the element's own ID, if any, nor be equal to the value of any of the other name
attributes on a
elements in the element's home subtree. If this attribute is present and the element has an ID, then the attribute's value must be
equal to the element's ID. In earlier versions of the language, this attribute was intended as a way to specify possible targets for fragment identifiers in URLs. The id
attribute should be used instead.
In the HTML syntax, specifying a DOCTYPE that is an obsolete permitted DOCTYPE will also trigger a warning.
Elements in the following list are entirely obsolete, and must not be used by authors:
applet
acronym
Use abbr
instead.
bgsound
Use audio
instead.
dir
Use ul
instead.
frame
frameset
noframes
Either use iframe
and CSS instead, or use server-side includes to generate complete pages with the various invariant parts merged in.
isindex
Use an explicit form
and text field combination instead.
listing
nextid
Use GUIDs instead.
noembed
plaintext
Use the "text/plain
" MIME type instead.
rb
Providing the ruby base directly inside the ruby
element is sufficient; the rb
element is unnecessary. Omit it altogether.
strike
Use del
instead if the element is marking an edit, otherwise use s
instead.
xmp
Use code
instead, and escape "<
" and "&
" characters as "<
" and "&
" respectively.
basefont
big
blink
center
font
marquee
multicol
nobr
spacer
tt
Use appropriate elements and/or CSS instead.
Where the tt
element would have been used for marking up keyboard input, consider the kbd
element; for variables, consider the var
element; for computer code, consider the code
element; and for computer output, consider the samp
element.
Similarly, if the big
element is being used to denote a heading, consider using the h1
element; if it is being used for marking up important passages, consider the strong
element; and if it is being used for highlighting text for reference purposes, consider the mark
element.
See also the text-level semantics usage summary for more suggestions with examples.
The following attributes are obsolete (though the elements are still part of the language), and must not be used by authors:
charset
on a
elementscharset
on link
elementsUse an HTTP Content-Type header on the linked resource instead.
coords
on a
elementsshape
on a
elementsmethods
on a
elementsmethods
on link
elementsUse the HTTP OPTIONS feature instead.
name
on a
elements (except as noted in the previous section)name
on embed
elementsname
on img
elementsname
on option
elementsUse the id
attribute instead.
rev
on a
elementsrev
on link
elementsUse the rel
attribute instead, with an opposite term. (For example, instead of rev="made"
, use rel="author"
.)
urn
on a
elementsurn
on link
elementsSpecify the preferred persistent identifier using the href
attribute instead.
nohref
on area
elementsOmitting the href
attribute is sufficient; the nohref
attribute is unnecessary. Omit it altogether.
profile
on head
elementsWhen used for declaring which meta
terms are used in the document, unnecessary; omit it altogether, and register the names.
When used for triggering specific user agent behaviors: use a link
element instead.
version
on html
elementsUnnecessary. Omit it altogether.
usemap
on input
elementslongdesc
on iframe
elementslongdesc
on img
elementsUse a regular a
element to link to the description, or (in the case of images) use an image map to provide a link from the image to the image's description.
lowsrc
on img
elementsUse a progressive JPEG image (given in the src
attribute), instead of using two separate images.
target
on link
elementsUnnecessary. Omit it altogether.
scheme
on meta
elementsUse only one scheme per field, or make the scheme declaration part of the value.
archive
on object
elementsclassid
on object
elementscode
on object
elementscodebase
on object
elementscodetype
on object
elementsUse the data
and type
attributes to invoke plugins. To set parameters with these names in particular, the param
element can be used.
declare
on object
elementsRepeat the object
element completely each time the resource is to be reused.
standby
on object
elementsOptimize the linked resource so that it loads quickly or, at least, incrementally.
type
on param
elementsvaluetype
on param
elementsUse the name
and value
attributes without declaring value types.
language
on script
elements (except as noted in the previous section)Use the type
attribute instead.
event
on script
elementsfor
on script
elementsUse DOM Events mechanisms to register event listeners. [DOMEVENTS]
datapagesize
on table
elementsUnnecessary. Omit it altogether.
summary
on table
elementsUse one of the techniques for describing tables given in the table
section instead.
abbr
on td
and th
elementsUse text that begins in an unambiguous and terse manner, and include any more elaborate text after that. The title
attribute can also be useful in including more detailed text, so that the cell's contents can be made terse.
axis
on td
and th
elementsdatasrc
on a
, applet
, button
, div
, frame
, iframe
, img
, input
, label
, legend
, marquee
, object
, option
, select
, span
, table
, and textarea
elementsdatafld
on a
, applet
, button
, div
, fieldset
, frame
, iframe
, img
, input
, label
, legend
, marquee
, object
, param
, select
, span
, and textarea
elementsdataformatas
on button
, div
, input
, label
, legend
, marquee
, object
, option
, select
, span
, and table
elementsUse script and a mechanism such as XMLHttpRequest
to populate the page dynamically. [XHR]
alink
on body
elementsbgcolor
on body
elementslink
on body
elementsmarginbottom
on body
elementsmarginheight
on body
elementsmarginleft
on body
elementsmarginright
on body
elementsmargintop
on body
elementsmarginwidth
on body
elementstext
on body
elementsvlink
on body
elementsclear
on br
elementsalign
on caption
elementsalign
on col
elementschar
on col
elementscharoff
on col
elementsvalign
on col
elementswidth
on col
elementsalign
on div
elementscompact
on dl
elementsalign
on embed
elementshspace
on embed
elementsvspace
on embed
elementsalign
on hr
elementscolor
on hr
elementsnoshade
on hr
elementssize
on hr
elementswidth
on hr
elementsalign
on h1
—h6
elementsalign
on iframe
elementsallowtransparency
on iframe
elementsframeborder
on iframe
elementshspace
on iframe
elementsmarginheight
on iframe
elementsmarginwidth
on iframe
elementsscrolling
on iframe
elementsvspace
on iframe
elementsalign
on input
elementshspace
on input
elementsvspace
on input
elementsalign
on img
elementsborder
on img
elements (except as noted in the previous section)hspace
on img
elementsvspace
on img
elementsalign
on legend
elementstype
on li
elementscompact
on menu
elementsalign
on object
elementsborder
on object
elementshspace
on object
elementsvspace
on object
elementscompact
on ol
elementsalign
on p
elementswidth
on pre
elementsalign
on table
elementsbgcolor
on table
elementscellpadding
on table
elementscellspacing
on table
elementsframe
on table
elementsrules
on table
elementswidth
on table
elementsalign
on tbody
, thead
, and tfoot
elementschar
on tbody
, thead
, and tfoot
elementscharoff
on tbody
, thead
, and tfoot
elementsvalign
on tbody
, thead
, and tfoot
elementsalign
on td
and th
elementsbgcolor
on td
and th
elementschar
on td
and th
elementscharoff
on td
and th
elementsheight
on td
and th
elementsnowrap
on td
and th
elementsvalign
on td
and th
elementswidth
on td
and th
elementsalign
on tr
elementsbgcolor
on tr
elementschar
on tr
elementscharoff
on tr
elementsvalign
on tr
elementscompact
on ul
elementstype
on ul
elementsbackground
on body
, table
, thead
, tbody
, tfoot
, tr
, td
, and th
elementsUse CSS instead.
The border
attribute on the table
element can be used to provide basic fallback styling for the purpose of making tables legible in browsing environments where CSS support is limited or absent, such as text-based browsers, WYSIWYG editors, and in situations where CSS support is disabled or the style sheet is lost. Only the empty string and the value "1
" may be used as border
values for this purpose. Other values are considered obsolete. To regulate the thickness of such borders, authors should instead use CSS.
The align
, alt
, archive
, code
, height
, hspace
, name
, object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.
The codeBase
IDL attribute must reflect the codebase
content attribute, which for the purposes of reflection is defined as containing a URL.
The behavior
, direction
, height
, hspace
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name.
The bgColor
IDL attribute must reflect the bgcolor
content attribute.
The scrollAmount
IDL attribute must reflect the scrollamount
content attribute. The default value is 6.
The scrollDelay
IDL attribute must reflect the scrolldelay
content attribute. The default value is 85.
The trueSpeed
IDL attribute must reflect the truespeed
content attribute.
The cols
and rows
IDL attributes of the frameset
element must reflect the respective content attributes of the same name.
The name
, scrolling
, and src
IDL attributes of the frame
element must reflect the respective content attributes of the same name.
The frameBorder
IDL attribute of the frame
element must reflect the element's frameborder
content attribute.
The longDesc
IDL attribute of the frame
element must reflect the element's longdesc
content attribute, which for the purposes of reflection is defined as containing a URL.
The marginHeight
IDL attribute of the frame
element must reflect the element's marginheight
content attribute.
The marginWidth
IDL attribute of the frame
element must reflect the element's marginwidth
content attribute.
The noResize
IDL attribute of the frame
element must reflect the element's noresize
content attribute.
The coords
, charset
, name
, rev
, and shape
IDL attributes of the a
element must reflect the respective content attributes of the same name.
The noHref
IDL attribute of the area
element must reflect the element's nohref
content attribute.
The color
, face
, and size
IDL attributes of the basefont
element must reflect the respective content attributes of the same name.
The text
IDL attribute of the body
element must reflect the element's text
content attribute.
The bgColor
IDL attribute of the body
element must reflect the element's bgcolor
content attribute.
The background
IDL attribute of the body
element must reflect the element's background
content attribute. (The background
content is not defined to contain a URL, despite rules regarding its handling in the rendering section above.)
The link
IDL attribute of the body
element must reflect the element's link
content attribute.
The aLink
IDL attribute of the body
element must reflect the element's alink
content attribute.
The vLink
IDL attribute of the body
element must reflect the element's vlink
content attribute.
The clear
IDL attribute of the br
element must reflect the content attribute of the same name.
The align
IDL attribute of the caption
element must reflect the content attribute of the same name.
The align
and width
IDL attributes of the col
element must reflect the respective content attributes of the same name.
The ch
IDL attribute of the col
element must reflect the element's char
content attribute.
The chOff
IDL attribute of the col
element must reflect the element's charoff
content attribute.
The vAlign
IDL attribute of the col
element must reflect the element's valign
content attribute.
The compact
IDL attribute of the dir
element must reflect the content attribute of the same name.
The align
IDL attribute of the div
element must reflect the content attribute of the same name.
The compact
IDL attribute of the dl
element must reflect the content attribute of the same name.
The name
and align
IDL attributes of the embed
element must reflect the respective content attributes of the same name.
The color
, face
, and size
IDL attributes of the font
element must reflect the respective content attributes of the same name.
The align
IDL attribute of the h1
–h6
elements must reflect the content attribute of the same name.
The align
, color
, size
, and width
IDL attributes of the hr
element must reflect the respective content attributes of the same name.
The noShade
IDL attribute of the hr
element must reflect the element's noshade
content attribute.
The version
IDL attribute of the html
element must reflect the content attribute of the same name.
The align
and scrolling
IDL attributes of the iframe
element must reflect the respective content attributes of the same name.
The frameBorder
IDL attribute of the iframe
element must reflect the element's frameborder
content attribute.
The longDesc
IDL attribute of the iframe
element must reflect the element's longdesc
content attribute, which for the purposes of reflection is defined as containing a URL.
The marginHeight
IDL attribute of the iframe
element must reflect the element's marginheight
content attribute.
The marginWidth
IDL attribute of the iframe
element must reflect the element's marginwidth
content attribute.
The name
, align
, border
, hspace
, and vspace
IDL attributes of the img
element must reflect the respective content attributes of the same name.
The longDesc
IDL attribute of the img
element must reflect the element's longdesc
content attribute, which for the purposes of reflection is defined as containing a URL.
The align
IDL attribute of the input
element must reflect the content attribute of the same name.
The useMap
IDL attribute of the input
element must reflect the element's usemap
content attribute.
The align
IDL attribute of the legend
element must reflect the content attribute of the same name.
The type
IDL attribute of the li
element must reflect the content attribute of the same name.
The charset
, rev
, and target
IDL attributes of the link
element must reflect the respective content attributes of the same name.
The compact
IDL attribute of the menu
element must reflect the content attribute of the same name.
The scheme
IDL attribute of the meta
element must reflect the content attribute of the same name.
The align
, archive
, border
, code
, declare
, hspace
, standby
, and vspace
IDL attributes of the object
element must reflect the
respective content attributes of the same name.
The codeBase
IDL attribute of the object
element must reflect the element's codebase
content attribute, which for the purposes of reflection is defined as containing a URL.
The codeType
IDL attribute of the object
element must reflect the element's codetype
content attribute.
The compact
IDL attribute of the ol
element must reflect the content attribute of the same name.
The align
IDL attribute of the p
element must reflect the content attribute of the same name.
The type
IDL attribute of the param
element must reflect the content attribute of the same name.
The valueType
IDL attribute of the param
element must reflect the element's valuetype
content attribute.
The width
IDL attribute of the pre
element must reflect the content attribute of the same name.
The align
, frame
, summary
, rules
, and width
, IDL attributes of the table
element must reflect the respective content attributes of the same name.
The bgColor
IDL attribute of the table
element must reflect the element's bgcolor
content attribute.
The cellPadding
IDL attribute of the table
element must reflect the element's cellpadding
content attribute.
The cellSpacing
IDL attribute of the table
element must reflect the element's cellspacing
content attribute.
The align
IDL attribute of the tbody
, thead
, and tfoot
elements must reflect the content attribute of the same name.
The ch
IDL attribute of the tbody
, thead
, and tfoot
elements must reflect the elements' char
content attributes.
The chOff
IDL attribute of the tbody
, thead
, and tfoot
elements must reflect the elements' charoff
content attributes.
The vAlign
IDL attribute of the tbody
, thead
, and tfoot
element must reflect the elements' valign
content attributes.
The abbr
, align
, axis
, height
, and width
IDL attributes of the td
and th
elements must reflect the respective content attributes of the same name.
The bgColor
IDL attribute of the td
and th
elements must reflect the elements' bgcolor
content attributes.
The ch
IDL attribute of the td
and th
elements must reflect the elements' char
content attributes.
The chOff
IDL attribute of the td
and th
elements must reflect the elements' charoff
content attributes.
The noWrap
IDL attribute of the td
and th
elements must reflect the elements' nowrap
content attributes.
The vAlign
IDL attribute of the td
and th
element must reflect the elements' valign
content attributes.
The align
IDL attribute of the tr
element must reflect the content attribute of the same name.
The bgColor
IDL attribute of the tr
element must reflect the element's bgcolor
content attribute.
The ch
IDL attribute of the tr
element must reflect the element's char
content attribute.
The chOff
IDL attribute of the tr
element must reflect the element's charoff
content attribute.
The vAlign
IDL attribute of the tr
element must reflect the element's valign
content attribute.
The compact
and type
IDL attributes of the ul
element must reflect the respective content attributes of the same name.
The attributes of the Document
object listed in the first column of the following table must reflect the content attribute on the body element with the name given in the corresponding cell in the second column on the same row, if the body element is a body
element (as opposed to a frameset
element). When there is no body element or if it is a frameset
element, the attributes must instead return the empty string on getting and do nothing on setting.
text/html
This registration is for community review and will be submitted to the IESG for review, approval, and registration with IANA.
charset
The charset
parameter may be provided to definitively specify the document's character encoding, overriding any character encoding declarations in the document. The parameter's value must be the name of the character encoding used to serialize the file, must be a valid character encoding name, and must be an ASCII case-insensitive match for the preferred MIME name for that encoding. [IANACHARSET]
Entire novels have been written about the security considerations that apply to HTML documents. Many are listed in this document, to which the reader is referred for more details. Some general concerns bear mentioning here, however:
HTML is scripted language, and has a large number of APIs (some of which are described in this document). Script can expose the user to potential risks of information leakage, credential leakage, cross-site scripting attacks, cross-site request forgeries, and a host of other problems. While the designs in this specification are intended to be safe if implemented correctly, a full implementation is a massive undertaking and, as with any software, user agents are likely to have security bugs.
Even without scripting, there are specific features in HTML which, for historical reasons, are required for broad compatibility with legacy content but that expose the user to unfortunate security problems. In particular, the img
element can be used in conjunction with some other features as a way to effect a port scan from the user's location on the Internet. This can expose local network topologies that the attacker would otherwise not be able to determine.
HTML relies on a compartmentalization scheme sometimes known as the same-origin policy. An origin in most cases consists of all the pages served from the same host, on the same port, using the same protocol.
It is critical, therefore, to ensure that any untrusted content that forms part of a site be hosted on a different origin than any sensitive content on that site. Untrusted content can easily spoof any other page on the same origin, read data from that origin, cause scripts in that origin to execute, submit forms to and from that origin even if they are protected from cross-site request forgery attacks by unique tokens, and make use of any third-party resources exposed to or rights granted to that origin.
html
" and "htm
" are commonly, but certainly not exclusively, used as the extension for HTML documents.TEXT
Fragment identifiers used with text/html
resources refer to the indicated part of the document.
text/html-sandboxed
This registration is for community review and will be submitted to the IESG for review, approval, and registration with IANA.
text/html
text/html
The purpose of the text/html-sandboxed
MIME type is to provide a way for content providers to indicate that they want the file to be interpreted in a manner that does not give the file's contents access to the rest of the site. This is achieved by assigning the Document
objects generated from resources labeled as text/html-sandboxed
unique origins.
To avoid having legacy user agents treating resources labeled as text/html-sandboxed
as regular text/html
files, authors should avoid using the .html
or .htm
extensions for resources labeled as text/html-sandboxed
.
Furthermore, since the text/html-sandboxed
MIME type impacts the origin security model, authors should be careful to prevent tampering with the MIME type labeling mechanism itself when documents are labeled as text/html-sandboxed
. If an attacker can cause a file to be served as text/html
instead of text/html-sandboxed
, then the sandboxing will not take effect and a cross-site scripting attack will become possible.
Beyond this, the type is identical to text/html
, and the same considerations apply.
text/html
text/html-sandboxed
type asserts that the resource is an HTML document using the HTML syntax.text/html
text/html-sandboxed
are heuristically indistinguishable from those labeled as text/html
.sandboxed
"TEXT
Fragment identifiers used with text/html-sandboxed
resources refer to the indicated part of the document.
application/xhtml+xml
This registration is for community review and will be submitted to the IESG for review, approval, and registration with IANA.
application/xml
[RFC3023]application/xml
[RFC3023]application/xml
[RFC3023]application/xml
[RFC3023]application/xml
[RFC3023]application/xhtml+xml
type asserts that the resource is an XML document that likely has a root element from the HTML namespace. As such, the relevant specifications are the XML specification, the Namespaces in XML specification, and this specification. [XML] [XMLNS]application/xml
[RFC3023]application/xml
[RFC3023]xhtml
" and "xht
" are sometimes used as extensions for XML resources that have a root element from the HTML namespace.TEXT
Fragment identifiers used with application/xhtml+xml
resources have the same semantics as with any XML MIME type. [RFC3023]
text/cache-manifest
This registration is for community review and will be submitted to the IESG for review, approval, and registration with IANA.
Cache manifests themselves pose no immediate risk unless sensitive information is included within the manifest. Implementations, however, are required to follow specific rules when populating a cache based on a cache manifest, to ensure that certain origin-based restrictions are honored. Failure to correctly implement these rules can result in information leakage, cross-site scripting attacks, and the like.
CACHE MANIFEST
", followed by either a U+0020 SPACE character, a U+0009 CHARACTER TABULATION (tab) character, a U+000A LINE FEED (LF) character, or a U+000D CARRIAGE RETURN (CR) character.appcache
"Fragment identifiers have no meaning with text/cache-manifest
resources.
An asterisk (*) in a cell indicates that the actual rules are more complicated than indicated in the table above.
† Categories in the "Parents" column refer to parents that list the given categories in their content model, not to elements that themselves are in those categories. For example, the a
element's "Parents" column says "phrasing", so any element whose content model contains the "phrasing" category could be a parent of an a
element. Since the "flow" category includes all the "phrasing" elements, that means the address
element could be a parent to an a
element.
Attribute | Element(s) | Description | Value |
---|---|---|---|
accept |
input |
Hint for expected file type in file upload controls | Set of comma-separated tokens* consisting of valid MIME types with no parameters or audio/* , video/* , or image/* |
accept-charset |
form |
Character encodings to use for form submission | Ordered set of unique space-separated tokens, ASCII case-insensitive, consisting of preferred MIME names of ASCII-compatible character encodings* |
accesskey |
HTML elements | Keyboard shortcut to activate or focus element | Ordered set of unique space-separated tokens, case-sensitive, consisting of one Unicode code point in length |
action |
form |
URL to use for form submission | Valid URL potentially surrounded by spaces |
alt |
area ; img ; input |
Replacement text for use when images are not available | Text* |
async |
script |
Execute script asynchronously | Boolean attribute |
autocomplete |
form ; input |
Prevent the user agent from providing autocompletions for the form control(s) | "on "; "off " |
autofocus |
button ; input ; keygen ; select ; textarea |
Automatically focus the form control when the page is loaded | Boolean attribute |
autoplay |
audio ; video |
Hint that the media resource can be started automatically when the page is loaded | Boolean attribute |
border |
border |
Explicit indication that the table element is not being used for layout purposes |
The empty string, or "1 " |
challenge |
keygen |
String to package with the generated and signed public key | Text |
charset |
meta |
Character encoding declaration | Preferred MIME name of an encoding* |
charset |
script |
Character encoding of the external script resource | Preferred MIME name of an encoding* |
checked |
command ; input |
Whether the command or control is checked | Boolean attribute |
cite |
blockquote ; del ; ins ; q |
Link to the source of the quotation or more information about the edit | Valid URL potentially surrounded by spaces |
class |
HTML elements | Classes to which the element belongs | Set of space-separated tokens |
cols |
textarea |
Maximum number of characters per line | Valid non-negative integer greater than zero |
colspan |
td ; th |
Number of columns that the cell is to span | Valid non-negative integer greater than zero |
content |
meta |
Value of the element | Text* |
contenteditable |
HTML elements | Whether the element is editable | "true "; "false " |
contextmenu |
HTML elements | The element's context menu | ID* |
controls |
audio ; video |
Show user agent controls | Boolean attribute |
coords |
area |
Coordinates for the shape to be created in an image map | Valid list of integers* |
data |
object |
Address of the resource | Valid non-empty URL potentially surrounded by spaces |
datetime |
del ; ins |
Date and (optionally) time of the change | Valid date string with optional time |
datetime |
time |
Value of the element | Valid date or time string* |
default |
track |
Enable the track if no other text track is more suitable. | Boolean attribute |
defer |
script |
Defer script execution | Boolean attribute |
dir |
HTML elements | The text directionality of the element | "ltr "; "rtl " |
dirname |
input ; textarea |
Name of form field to use for sending the element's directionality in form submission | Text* |
disabled |
button ; command ; fieldset ; input ; keygen ; optgroup ; option ; select ; textarea |
Whether the form control is disabled | Boolean attribute |
draggable |
HTML elements | Whether the element is draggable | "true "; "false " |
dropzone |
HTML elements | Accepted item types for drag-and-drop | Unordered set of unique space-separated tokens, ASCII case-insensitive, consisting of accepted types and drag feedback* |
enctype |
form |
Form data set encoding type to use for form submission | "application/x-www-form-urlencoded "; "multipart/form-data "; "text/plain " |
for |
label |
Associate the label with form control | ID* |
for |
output |
Specifies controls from which the output was calculated | Unordered set of unique space-separated tokens, case-sensitive, consisting of IDs* |
form |
button ; fieldset ; input ; keygen ; label ; meter ; object ; output ; progress ; select ; textarea |
Associates the control with a form element |
ID* |
formaction |
button ; input |
URL to use for form submission | Valid URL potentially surrounded by spaces |
formenctype |
button ; input |
Form data set encoding type to use for form submission | "application/x-www-form-urlencoded "; "multipart/form-data "; "text/plain " |
formmethod |
button ; input |
HTTP method to use for form submission | "GET "; "POST " |
formnovalidate |
button ; input |
Bypass form control validation for form submission | Boolean attribute |
formtarget |
button ; input |
Browsing context for form submission | Valid browsing context name or keyword |
headers |
td ; th |
The header cells for this cell | Unordered set of unique space-separated tokens, case-sensitive, consisting of IDs* |
height |
canvas ; embed ; iframe ; img ; input ; object ; video |
Vertical dimension | Valid non-negative integer |
hidden |
Whether the element is relevant | Boolean attribute | |
high |
meter |
Low limit of high range | Valid floating point number* |
href |
a ; area |
Address of the hyperlink | Valid URL potentially surrounded by spaces |
href |
link |
Address of the hyperlink | Valid non-empty URL potentially surrounded by spaces |
href |
base |
Document base URL | Valid URL potentially surrounded by spaces |
hreflang |
a ; area ; link |
Language of the linked resource | Valid BCP 47 language tag |
http-equiv |
meta |
Pragma directive | Text* |
icon |
command |
Icon for the command | Valid non-empty URL potentially surrounded by spaces |
id |
HTML elements | The element's ID | Text* |
ismap |
img |
Whether the image is a server-side image map | Boolean attribute |
keytype |
keygen |
The type of cryptographic key to generate | Text* |
kind |
track |
The type of text track | "subtitles "; "captions "; "descriptions "; "chapters "; "metadata " |
label |
command ; menu ; optgroup ; option ; track |
User-visible label | Text |
lang |
HTML elements | Language of the element | Valid BCP 47 language tag or the empty string |
list |
input |
List of autocomplete options | ID* |
loop |
audio ; video |
Whether to loop the media resource | Boolean attribute |
low |
meter |
High limit of low range | Valid floating point number* |
manifest |
html |
Application cache manifest | Valid non-empty URL potentially surrounded by spaces |
max |
input |
Maximum value | varies* |
max |
meter ; progress |
Upper bound of range | Valid floating point number* |
maxlength |
input ; textarea |
Maximum length of value | Valid non-negative integer |
media |
a ; area ; link ; source ; style |
Applicable media | Valid media query |
mediagroup |
audio ; video |
Groups media elements together with an implicit MediaController |
Text |
method |
form |
HTTP method to use for form submission | "GET "; "POST " |
min |
input |
Minimum value | varies* |
min |
meter |
Lower bound of range | Valid floating point number* |
multiple |
input ; select |
Whether to allow multiple values | Boolean attribute |
name |
button ; fieldset ; input ; keygen ; output ; select ; textarea |
Name of form control to use for form submission and in the form.elements API |
Text* |
name |
form |
Name of form to use in the document.forms API |
Text* |
name |
iframe ; object |
Name of nested browsing context | Valid browsing context name or keyword |
name |
map |
Name of image map to reference from the usemap attribute |
Text* |
name |
meta |
Metadata name | Text* |
name |
param |
Name of parameter | Text |
novalidate |
form |
Bypass form control validation for form submission | Boolean attribute |
open |
details |
Whether the details are visible | Boolean attribute |
optimum |
meter |
Optimum value in gauge | Valid floating point number* |
pattern |
input |
Pattern to be matched by the form control's value | Regular expression matching the JavaScript Pattern production |
placeholder |
input ; textarea |
User-visible label to be placed within the form control | Text* |
poster |
video |
Poster frame to show prior to video playback | Valid non-empty URL potentially surrounded by spaces |
preload |
audio ; video |
Hints how much buffering the media resource will likely need | "none "; "metadata "; "auto " |
pubdate |
time |
Whether the element's value represents a publication time for the nearest article or body |
Boolean attribute |
radiogroup |
command |
Name of group of commands to treat as a radio button group | Text |
readonly |
input ; textarea |
Whether to allow the value to be edited by the user | Boolean attribute |
rel |
a ; area ; link |
Relationship between the document containing the hyperlink and the destination resource | Set of space-separated tokens* |
required |
input ; select ; textarea |
Whether the control is required for form submission | Boolean attribute |
reversed |
ol |
Number the list backwards | Boolean attribute |
rows |
textarea |
Number of lines to show | Valid non-negative integer greater than zero |
rowspan |
td ; th |
Number of rows that the cell is to span | Valid non-negative integer |
sandbox |
iframe |
Security rules for nested content | Unordered set of unique space-separated tokens, ASCII case-insensitive, consisting of "allow-same-origin ", "allow-forms ", and "allow-scripts " |
spellcheck |
HTML elements | Whether the element is to have its spelling and grammar checked | "true "; "false " |
scope |
th |
Specifies which cells the header cell applies to | "row "; "col "; "rowgroup "; "colgroup " |
scoped |
style |
Whether the styles apply to the entire document or just the parent subtree | Boolean attribute |
seamless |
iframe |
Whether to apply the document's styles to the nested content | Boolean attribute |
selected |
option |
Whether the option is selected by default | Boolean attribute |
shape |
area |
The kind of shape to be created in an image map | "circle "; "default "; "poly "; "rect " |
size |
input ; select |
Size of the control | Valid non-negative integer greater than zero |
sizes |
link |
Sizes of the icons (for rel ="icon ") |
Unordered set of unique space-separated tokens, ASCII case-insensitive, consisting of sizes* |
span |
col ; colgroup |
Number of columns spanned by the element | Valid non-negative integer greater than zero |
src |
audio ; embed ; iframe ; img ; input ; script ; source ; track ; video |
Address of the resource | Valid non-empty URL potentially surrounded by spaces |
srcdoc |
iframe |
A document to render in the iframe |
The source of an iframe srcdoc document* |
srclang |
track |
Language of the text track | Valid BCP 47 language tag |
start |
ol |
Ordinal value of the first item | Valid integer |
step |
input |
Granularity to be matched by the form control's value | Valid floating point number greater than zero, or "any " |
style |
HTML elements | Presentational and formatting instructions | CSS declarations* |
tabindex |
HTML elements | Whether the element is focusable, and the relative order of the element for the purposes of sequential focus navigation | Valid integer |
target |
a ; area |
Browsing context for hyperlink navigation | Valid browsing context name or keyword |
target |
base |
Default browsing context for hyperlink navigation and form submission | Valid browsing context name or keyword |
target |
form |
Browsing context for form submission | Valid browsing context name or keyword |
title |
HTML elements | Advisory information for the element | Text |
title |
abbr ; dfn |
Full term or expansion of abbreviation | Text |
title |
command |
Hint describing the command | Text |
title |
link |
Title of the link | Text |
title |
link ; style |
Alternative style sheet set name | Text |
type |
a ; area ; link |
Hint for the type of the referenced resource | Valid MIME type |
type |
button |
Type of button | "submit "; "reset "; "button " |
type |
button ; input |
Type of form control | input type keyword |
type |
command |
Type of command | "command "; "checkbox "; "radio " |
type |
embed ; object ; script ; source ; style |
Type of embedded resource | Valid MIME type |
type |
menu |
Type of menu | "context "; "toolbar " |
usemap |
img ; object |
Name of image map to use | Valid hash-name reference* |
value |
button ; option |
Value to be used for form submission | Text |
value |
input |
Value of the form control | varies* |
value |
li |
Ordinal value of the list item | Valid integer |
value |
meter ; progress |
Current value of the element | Valid floating point number |
value |
param |
Value of parameter | Text |
width |
canvas ; embed ; iframe ; img ; input ; object ; video |
Horizontal dimension | Valid non-negative integer |
wrap |
textarea |
How the value of the form control is to be wrapped for form submission | "soft "; "hard " |
An asterisk (*) in a cell indicates that the actual rules are more complicated than indicated in the table above.
Event | Interface | Description |
---|---|---|
DOMContentLoaded |
Event |
Fired at the Document once it and its scripts have loaded, without waiting for other subresources |
abort |
Event |
Fired at the Window when the download was aborted by the user |
afterprint |
Event |
Fired at the Window after printing |
beforeprint |
Event |
Fired at the Window before printing |
beforeunload |
BeforeUnloadEvent |
Fired at the Window when the page is about to be unloaded, in case the page would like to show a warning prompt |
blur |
Event |
Fired at nodes losing focus |
change |
Event |
Fired at controls when the user commits a value change |
click |
Event |
Fired at an element before its activation behavior is run |
contextmenu |
Event |
Fired at elements when the user requests their context menu |
error |
Event |
Fired at elements when network and script errors occur |
focus |
Event |
Fired at nodes gaining focus |
hashchange |
HashChangeEvent |
Fired at the Window when the fragment identifier part of the document's current address changes |
input |
Event |
Fired at controls when the user changes the value |
invalid |
Event |
Fired at controls during form validation if they do not satisfy their constraints |
load |
Event |
Fired at the Window when the document has finished loading; fired at an element containing a resource (e.g. img , embed ) when its resource has finished loading |
message |
MessageEvent |
Fired at an object when the object receives a message |
offline |
Event |
Fired at the Window when the network connections fails |
online |
Event |
Fired at the Window when the network connections returns |
pagehide |
PageTransitionEvent |
Fired at the Window when the page's entry in the session history stops being the current entry |
pageshow |
PageTransitionEvent |
Fired at the Window when the page's entry in the session history becomes the current entry |
popstate |
PopStateEvent |
Fired at the Window when the user navigates the session history |
readystatechange |
Event |
Fired at the Document when it finishes parsing and again when all its subresources have finished loading |
reset |
Event |
Fired at a form element when it is reset |
show |
Event |
Fired at a menu element when it is shown as a context menu |
submit |
Event |
Fired at a form element when it is submitted |
unload |
Event |
Fired at the Window object when the page is going away |
See also media element events, application cache events, and drag-and-drop events.
TrackList
objectsa
link
elementa
element (2) (3) (4) (5) (6)dfn
element (2)img
element (2) (3)a
and area
elements (2) (3) (4) (5)alternate
"author
" (2)bookmark
"external
"help
" (2)license
"nofollow
"noreferrer
"prefetch
"search
"sidebar
"tag
"next
"prev
"abbr
title
attributedfn
elementabbr
element (2) (3) (4) (5) (6) (7) (8) (9)abbr
td
and th
elementsabbr
align
, axis
, height
, and width
IDL attributes of the td
and th
elements must reflect the respective content attributes of the same name.abort
ABORT_ERR
about:legacy-compat
about:srcdoc
accept
alt
, max
, min
, multiple
, pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)accept
input
element (2) (3)accept-charset
form
element (2) (3)acceptCharset
form
element (2)accesskey
accesskey
attribute (2) (3) (4)accessKey
...
content attribute.accesskey
attributeacronym
action
formaction
content attributes, if specified, must have a value that is a valid non-empty URL potentially surrounded by spaces.form
element (2)formaction
attribute, if the element is a submit button and has such an attribute, or the value of its form owner's ...
attribute, if it has one, or else the empty string.action
target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited
to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the
content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.form
elementimg
elementiframe
elementobject
elementWindow
object (2)address
article
elementfooter
elementaddress
element (2) (3) (4) (5) (6) (7)align
caption
elementsalign
col
elementsalign
div
elementsalign
embed
elementsembed
elementalign
hr
elementsalign
h1
—h6
elementsalign
iframe
elementsalign
input
elementsalign
img
elementsalign
legend
elementsalign
object
elementsalign
p
elementsalign
table
elementsalign
tbody
, thead
, and tfoot
elementsalign
td
and th
elementsalign
tr
elementsalign
alt
, archive
, code
, height
, hspace
, name
, object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.align
caption
element must reflect the content attribute of the same name.align
width
IDL attributes of the col
element must reflect the respective content attributes of the same name.align
div
element must reflect the content attribute of the same name.align
name
and ... IDL attributes of the embed
element must reflect the respective content attributes of the same name.align
h1
–h6
elements must reflect the content attribute of the same name.align
color
, size
, and width
IDL attributes of the hr
element must reflect the respective content attributes of the same name.align
scrolling
IDL attributes of the iframe
element must reflect the respective content attributes of the same name.align
name
, ..., border
, hspace
, and vspace
IDL attributes of the img
element must reflect the respective content attributes of the same name.align
input
element must reflect the content attribute of the same name.align
legend
element must reflect the content attribute of the same name.align
archive
, border
, code
, declare
, hspace
, standby
, and vspace
IDL attributes of the object
element must reflect the respective content attributes of the same name.align
p
element must reflect the content attribute of the same name.align
frame
, summary
, rules
, and width
, IDL attributes of the table
element must reflect the respective content attributes of the same name.align
tbody
, thead
, and tfoot
elements must reflect the content attribute of the same name.align
abbr
, ..., axis
, height
, and width
IDL attributes of the td
and th
elements must reflect the respective content attributes of the same name.align
tr
element must reflect the content attribute of the same name.alink
body
elementsaLink
body
element must reflect the element's ...
content attribute.allowtransparency
alt
src
attribute is the embedded content; the value of the ... attribute provides equivalent content for those who cannot process images or who have image loading disabled.img
element (2) (3) (4)alt
src
, useMap
, and isMap
each must reflect the respective content attributes of the same name.img
element (2)alt
area
element has an href
attribute, then the area
element represents a hyperlink. In this case, the ... attribute must be present. It specifies the text of the hyperlink. Its value must be text that, when presented with the texts specified for the other hyperlinks of the image map, and with the alternative text of the image, but without the image itself, provides the user with the same kind of choice as the hyperlink would when used without its text but with its shape applied to the image. The alt
attribute may be left blank if there is another area
element in the same image map that points to
the same resource and has a non-blank alt
attribute.area
element (2) (3) (4) (5)alt
coords
, href
, target
, rel
, media
, hreflang
, and type
, each must reflect the respective content attributes of the same name.area
element (2)alt
accept
, ..., max
, min
, multiple
, pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)alt
alt
attribute must also be present, and must contain a non-empty string.input
element (2) (3)alt
align
, ..., archive
, code
, height
, hspace
, name
, object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.alternate
alternate
" (2) (3) (4) (5) (6) (7) (8) (9) (10)stylesheet
"alternative
TrackList
objectsiframe
srcdoc
documenthead
elementiframe
elementapplication-name
application/x-www-form-urlencoded
application/xhtml+xml
application/xhtml+xml
(2) (3)Window
objectarchive
object
elementsarchive
align
, alt
, ..., code
, height
, hspace
, name
, object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.archive
align
, ..., border
, code
, declare
, hspace
, standby
, and vspace
IDL attributes of the object
element must reflect the respective content attributes of the same name.area
link
elementmap
element (2)area
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)a
and area
elements (2) (3) (4) (5)alternate
"author
" (2)bookmark
"external
"help
" (2)license
"nofollow
"noreferrer
"prefetch
"search
"sidebar
"tag
"next
"prev
"article
section
elementarticle
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)address
elementblockquote
elementdiv
elementtime
element (2) (3) (4) (5)author
"bookmark
" (2)lang
and xml:lang
attributes (2)meta
elementscript
elementiframe
elementform
element (2)step
attributeicon
" (2)dropzone
attribute (2) (3)text/html
form
elementaside
aside
element (2) (3) (4) (5)ins
elementasync
defer
attributes are boolean attributes that indicate how the script should be executed. The defer
and async
attributes must not be specified if the src
attribute is not present.script
element (2) (3) (4) (5) (6) (7) (8) (9)async
async
IDL attribute must return true, and on setting, the "force-async" flag must first be unset, and then the content attribute must be removed if the IDL attribute's new value is false, and must be set to the empty string if the IDL attribute's new value is true. If the element's "force-async" flag is not set, the IDL attribute must reflect the ...
content attribute.script
element (2) (3)form
elementbutton
elementaudio
audio
element (2) (3) (4) (5) (6)source
elementauto
dir
attribute (2)bdi
elementdir
attribute (2)autocomplete
on
keyword maps to the on state, and the off
keyword maps to the off state. The attribute may also be omitted. The missing value default is the on state. The off state indicates that by default, input
elements in the form will have their resulting autocompletion state set to off; the on state indicates that by default, input
elements in the form will have their resulting autocompletion state set to on.form
element (2)autocomplete
attribute (2)autocomplete
form
element (2)autocomplete
type
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only
non-negative numbers.input
element (2)autocomplete
on
keyword maps to the on state, and the off
keyword maps to the off state. The attribute may also be omitted. The missing value default is the default state.input
element (2) (3)autocomplete
attribute (2)autofocus
input
element (2)button
element (2)select
element (2)textarea
element (2)keygen
element (2)autofocus
input
elementbutton
elementselect
elementtextarea
elementkeygen
elementautoplay
video
element (2)audio
element (2)autoplay
axis
td
and th
elementsaxis
abbr
, align
, ..., height
, and width
IDL attributes of the td
and th
elements must reflect the respective content attributes of the same name.b
cite
element (2)b
element (2) (3) (4) (5) (6) (7) (8) (9) (10)u
elementbackground
body
, table
, thead
, tbody
, tfoot
, tr
, td
, and th
elementsbackground
body
element must reflect the element's ...
content attribute. (The ...
content is not defined to contain a URL, despite rules regarding its handling in the rendering section above.)base
html
elementbase
element (2) (3) (4) (5) (6) (7) (8) (9)meta
elementiframe
elementbasefont
bdi
dir
attribute (2)bdi
element (2) (3)bdo
bdo
element (2)behavior
bgcolor
body
elementsbgcolor
table
elementsbgcolor
td
and th
elementsbgcolor
tr
elementsbgColor
bgcolor
content attribute.bgColor
body
element must reflect the element's ...
content attribute.bgColor
table
element must reflect the element's ...
content attribute.bgColor
td
and th
elements must reflect the elements' ...
content attributes.bgColor
tr
element must reflect the element's ...
content attribute.bgsound
blockquote
blockquote
element (2) (3) (4) (5) (6) (7) (8)body
html
elementbody
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)address
elementbold
style
elementscript
elementol
elementtime
elementimg
elementiframe
elementinput
elementreadonly
attributerequired
attributemultiple
attributeselect
element (2)optgroup
elementoption
element (2)textarea
element (2)details
elementcommand
element (2)hidden
attributeborder
table
element to explicitly indicate that the table
element is not being used for layout purposes. If specified, the attribute's value must either be the empty string or the value "1
". The attribute is used by certain user agents as an indication that borders should be drawn around cells of the table.table
element (2)border
table
element (2)border
img
elements (except as noted in the previous section)border
object
elementsborder
name
, align
, ..., hspace
, and vspace
IDL attributes of the img
element must reflect the respective content attributes of the same name.border
align
, archive
, ..., code
, declare
, hspace
, standby
, and vspace
IDL attributes of the object
element must reflect the respective content attributes of the same name.br
br
element (2) (3) (4) (5) (6) (7)base
element (2)img
elementiframe
element (2) (3)a
and area
elementssidebar
"History
interface (2)Location
interface (2)button
input
elementcached
call(...)
canplay
canplay
canplaythrough
canplaythrough
canvas
canvas
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19)caption
table
element (2) (3) (4) (5) (6)caption
element (2) (3)colgroup
elementtbody
elementthead
elementtfoot
element (2)tr
elementcaptions
track
elementtrack
element (2)captions
ol
elementtd
and th
elementsoutput
elementaccesskey
attributecellpadding
table
elementscellPadding
table
element must reflect the element's ...
content attribute.cellspacing
table
elementscellSpacing
table
element must reflect the element's ...
content attribute.center
ch
col
element must reflect the element's char
content attribute.ch
tbody
, thead
, and tfoot
elements must reflect the elements' char
content attributes.ch
td
and th
elements must reflect the elements' char
content attributes.ch
tr
element must reflect the element's char
content attribute.challenge
keygen
element (2)challenge
keygen
element (2)chapters
track
elementtrack
elementchapters
char
col
elementschar
tbody
, thead
, and tfoot
elementschar
td
and th
elementschar
tr
elementsmeta
element (2)text/html
(2)charoff
col
elementscharoff
tbody
, thead
, and tfoot
elementscharoff
td
and th
elementscharoff
tr
elementscharset
UTF-8
" (and the document is therefore forced to use UTF-8 as its encoding).meta
element (2) (3) (4) (5) (6) (7)charset
src
attribute is not present. If the attribute is set, its value must be a valid character encoding name, must be an ASCII case-insensitive match for the preferred MIME name for that encoding, and must match the encoding given in the charset
parameter of the Content-Type metadata of the external file, if any. [IANACHARSET]script
element (2) (3)charset
src
, type
, ..., and defer
, each must reflect the respective content attributes of the same name.script
element (2)charset
a
elementscharset
link
elementscharset
coords
, ..., name
, rev
, and shape
IDL attributes of the a
element must reflect the respective content attributes of the same name.charset
rev
, and target
IDL attributes of the link
element must reflect the respective content attributes of the same name.checkbox
input
elementinput
element (2) (3)checkbox
command
" keyword maps to the Command state, the "..." keyword maps to the Checkbox state, and the "radio
" keyword maps to the Radio state. The missing value default is the Command state.command
elementcommand
element (2) (3)checked
input
element.input
element (2) (3) (4) (5)checked
type
attribute is in either the Checkbox state or the Radio state.command
element (2)checked
label
, icon
, disabled
, ..., and radiogroup
IDL attributes must reflect the respective content attributes of the same name.command
element (2)checking
CHECKING
chOff
col
element must reflect the element's charoff
content attribute.chOff
tbody
, thead
, and tfoot
elements must reflect the elements' charoff
content attributes.chOff
td
and th
elements must reflect the elements' charoff
content attributes.chOff
tr
element must reflect the element's charoff
content attribute.circle
area
elementarea
element (2)cite
blockquote
must be quoted from another source, whose address, if it has one, may be cited in the ... attribute.blockquote
element (2) (3)cite
cite
content attribute.blockquote
element (2)cite
blockquote
element (2)cite
element (2) (3) (4) (5) (6) (7)u
elementcite
q
element must be quoted from another source, whose address, if it has one, may be cited in the ... attribute. The source may be fictional, as when quoting characters in a novel or screenplay.q
element (2) (3)cite
ins
elementdel
elementins
and del
elements (2) (3)cite
...
content attribute. The dateTime
IDL attribute must reflect the element's datetime
content attribute.ins
and del
elements (2)class
class
attribute (2) (3) (4)data-*
attributesdiv
elementi
elementb
elementspan
element (2)classid
clear
br
elementsclear
br
element must reflect the content attribute of the same name.code
pre
elementcode
element (2) (3) (4)code
object
elementscode
align
, alt
, archive
, ..., height
, hspace
, name
, object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.code
align
, archive
, border
, ..., declare
, hspace
, standby
, and vspace
IDL attributes of the object
element must reflect the respective content attributes of the same name.codebase
object
elementscodeBase
codebase
content attribute, which for the purposes of reflection is defined as containing a URL.codeBase
object
element must reflect the element's ...
content attribute, which for the purposes of reflection is defined as containing a URL.codetype
object
elementscodeType
object
element must reflect the element's ...
content attribute.col
colgroup
element (2)col
element (2) (3)col
th
elementcolgroup
table
elementcolgroup
element (2) (3)col
element (2) (3) (4)tbody
elementthead
elementtfoot
element (2)tr
elementcolgroup
th
element (2)color
input
elementcolor
hr
elementscolor
face
, and size
IDL attributes of the basefont
element must reflect the respective content attributes of the same name.color
face
, and size
IDL attributes of the font
element must reflect the respective content attributes of the same name.color
align
, ..., size
, and width
IDL attributes of the hr
element must reflect the respective content attributes of the same name.cols
cols
attribute is specified, its value must be a valid non-negative integer greater than zero.textarea
element (2) (3) (4)cols
placeholder
, required
, rows
, and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The
cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative
numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.textarea
element (2) (3) (4)cols
rows
IDL attributes of the frameset
element must reflect the respective content attributes of the same name.colspan
td
and th
elements may have a ... content attribute specified, whose value must be a valid non-negative integer greater than zero.td
elementth
elementtd
and th
elementscolSpan
td
and th
elements (2)command
command
element (2) (3)command
checkbox
" keyword maps to the Checkbox state, and the "radio
" keyword maps to the Radio state. The missing value default is the Command state.command
elementcommand
element (2) (3)iframe
element (2) (3)compact
dl
elementscompact
ol
elementscompact
ul
elementscompact
dir
element must reflect the content attribute of the same name.compact
dl
element must reflect the content attribute of the same name.compact
ol
element must reflect the content attribute of the same name.compact
type
IDL attributes of the ul
element must reflect the respective content attributes of the same name.map
elementcontent
name
and ... IDL attributes must reflect the respective content attributes of the same name. The IDL attribute httpEquiv
must reflect the content attribute http-equiv
.meta
element (2)contentDocument
Document
object of the active document of the iframe
element's nested browsing context.iframe
element (2)contentDocument
Document
object of the active document of the object
element's nested browsing context, if it has one; otherwise, it must return null.object
element (2)contenteditable
contenteditable
attribute (2) (3)contentWindow
WindowProxy
object of the iframe
element's nested browsing context.iframe
element (2)contentWindow
WindowProxy
object of the object
element's nested browsing context, if it has one; otherwise, it must return null.object
element (2)controls
video
element (2) (3)audio
element (2) (3)controls
coords
shape
attribute.area
element (2) (3) (4) (5) (6) (7)coords
alt
, ..., href
, target
, rel
, media
, hreflang
, and type
, each must reflect the respective content attributes of the same name.area
element (2)coords
a
elementscoords
charset
, name
, rev
, and shape
IDL attributes of the a
element must reflect the respective content attributes of the same name.createLink
Document
History
interface (2)Location
interfaceHistory
interface (2)data-*
attributes (2) (3) (4)data
object
element (2) (3)data
type
, name
, and useMap
each must reflect the respective content attributes of the same name.object
element (2)data-
data-*
attributes (2) (3) (4)data:
URLcanvas
elementDATA_CLONE_ERR
datafld
dataformatas
datalist
list
attribute (2) (3) (4) (5) (6) (7)multiple
attributeinput
element APIs (2)datalist
element (2) (3) (4) (5)option
element (2)datapagesize
datasrc
DataTransfer
interface (2) (3) (4)DataTransferItems
interfaceDataTransferItem
interfaceDragEvent
interface (2) (3)DataTransferItems
interface (2) (3) (4)DataTransferItem
interface (2) (3)DataTransfer
interface (2)DataTransferItems
interface (2) (3)time
element (2)input
element (2) (3)input
element APIsinput
element (2)datetime
time
element (2) (3) (4) (5) (6) (7)dateTime
...
content attribute.time
element (2)datetime
ins
elementdel
elementins
and del
elements (2) (3)dateTime
cite
IDL attribute must reflect the element's cite
content attribute. The ... IDL attribute must reflect the element's ...
content attribute.ins
and del
elements (2)datetime
input
elementdatetime-local
input
elementdd
dl
element (2) (3)dt
element (2)dd
element (2) (3) (4)ol
elementdeclare
object
elementsdeclare
align
, archive
, border
, code
, ..., hspace
, standby
, and vspace
IDL attributes of the object
element must reflect the respective content attributes of the same name.default
track
element with the same parent node with the default
attribute specified.track
element (2) (3)default
src
, srclang
, label
, and ... IDL attributes must reflect the respective content attributes of the same name. The kind
IDL attribute must reflect the content attribute of the same name, limited to only known values.track
element (2)default
area
elementautocomplete
attribute is an enumerated attribute. The attribute has three states. The on
keyword maps to the on state, and the off
keyword maps to the off state. The attribute may also be omitted. The missing value default is the ... state.autocomplete
attribute (2)area
element (2)defaultChecked
input
element (2)defaultMuted
defaultSelected
option
element (2)defaultValue
input
element (2)defer
async
and ... attributes are boolean attributes that indicate how the script should be executed. The defer
and async
attributes must not be specified if the src
attribute is not present.script
element (2) (3) (4) (5) (6) (7) (8)defer
src
, type
, charset
, and ..., each must reflect the respective content attributes of the same name.script
element (2)dfn
element (2)abbr
elementdel
s
elementdel
element (2) (3)ins
and del
elements (2)delete
description
description
TrackList
objectsdescriptions
track
elementtrack
element (2)descriptions
details
details
element (2) (3) (4) (5) (6)summary
element (2)dfn
dl
elementdt
elementdd
elementdfn
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)i
elementimg
elementiframe
elementembed
elementobject
elementvideo
elementdir
dir
attribute (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)bdi
element (2)bdo
element (2)span
elementdir
...
content attribute of that element, limited to only known values.dir
attribute (2)dir
HTMLDocument
objects must reflect the ...
content attribute of the html
element, if any, limited to only known values. If there is no such element, then the attribute must return the empty string and do nothing on setting.dir
attributedirection
dirName
accept
, alt
, max
, min
, multiple
, pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective
content attributes of the same name. The ... IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)dirname
dirname
attribute.input
element (2) (3) (4)dirname
attribute (2)dirname
dirname
attribute.textarea
element (2) (3) (4)dirName
cols
, placeholder
, required
, rows
, and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The cols
attribute's default value is 20. The rows
attribute's default value is 2. The ... IDL attribute must reflect the ...
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.textarea
element (2)disabled
link
element defines a style sheet link, then the disabled
attribute behaves as defined for the alternative style sheets DOM. For all other link
elements it always return false and does nothing on setting.link
element (2) (3)disabled
style
element (2)disabled
fieldset
element, excluding those that are descendants of the fieldset
element's first legend
element child, if any, to be disabled.fieldset
element (2)disabled
fieldset
element (2)disabled
option
elements together.optgroup
element (2)option
elementdisabled
label
attributes must reflect the respective content attributes of the same name.optgroup
element (2)disabled
option
element is ... if its disabled
attribute is present or if it is a child of an optgroup
element whose ...
attribute is present.option
element (2) (3)option
element is ... if its ...
attribute is present or if it is a child of an optgroup
element whose ...
attribute is present.datalist
elementoptgroup
elementoption
elementdisabled
label
IDL attributes must reflect the respective content attributes of the same name. The defaultSelected
IDL attribute must reflect the selected
content attribute.option
element (2)disabled
input
element (2)button
element (2)select
element (2)textarea
element (2)keygen
element (2)...
attribute is set, or if it is a descendant of a fieldset
element whose ...
attribute is set and is not a descendant of that fieldset
element's first legend
element child, if any.fieldset
elementdisabled
...
content attribute.input
elementbutton
elementselect
elementtextarea
elementkeygen
elementdisabled
command
element (2) (3)disabled
label
, icon
, ..., checked
, and radiogroup
IDL attributes must reflect the respective content attributes of the same name.command
element (2)div
section
elementnav
elementdiv
element (2) (3) (4) (5) (6)dropzone
attributedl
dl
element (2) (3) (4) (5) (6) (7)dt
element (2) (3)dd
element (2) (3)dfn
elementiframe
elementdocument.write()
document.writeln()
innerHTML
(2) (3)outerHTML
insertAdjacentHTML()
head
elementbase
elementstyle
elementbody
element (2)time
elementiframe
element (2) (3) (4)object
elementform
elementlabel
elementoutput
elementWindow
objectHistory
interfaceLocation
interfacetext/html-sandboxed
link
elementiframe
elementtd
and th
elementsoutput
elementDOMSTRING_SIZE_ERR
link
elementa
elementarea
elementdownloading
DOWNLOADING
DataTransfer
interfaceDataTransferItems
interface (2) (3) (4) (5)dragenter
DragEvent
interface (2) (3)draggable
draggable
attribute (2) (3) (4)dragleave
dragstart
DataTransfer
interfacedropzone
dropzone
attribute (2) (3) (4)dropzone
dropzone
attributedt
dl
element (2) (3)dt
element (2) (3) (4) (5)dd
element (2)durationchange
durationchange
input
element (2)em
em
element (2) (3) (4) (5)small
element (2)i
elementb
elementu
elementmark
elementemail
input
elementembed
embed
element (2) (3) (4)img
element (2)iframe
element (2)embed
element (2)object
element (2)video
element (2)audio
element (2)canvas
element (2) (3) (4) (5)data-*
attributesemptied
emptied
meta
element (2) (3)enctype
formenctype
content attributes are enumerated attributes with the following keywords and states:form
element (2)formenctype
attribute, then the element's enctype is that attribute's state; otherwise, it is the form owner's ...
attribute's state.enctype
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and ... IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the ...
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.form
elementended
dir
attributetrack
elementarea
elementth
elementform
elementinput
elementautocomplete
attributebutton
elementtextarea
elementkeygen
elementcommand
elementmenu
elementcontenteditable
attributedraggable
attributeerror
error
body
element (2) (3)body
element (2) (3) (4)TrackList
objects (2)face
color
, ..., and size
IDL attributes of the basefont
element must reflect the respective content attributes of the same name.face
color
, ..., and size
IDL attributes of the font
element must reflect the respective content attributes of the same name.iframe
elementcanvas
element (2) (3) (4) (5)fieldset
div
elementfieldset
element (2) (3) (4) (5) (6) (7) (8) (9) (10)legend
element (2)figcaption
li
elementfigure
element (2) (3) (4)figcaption
element (2) (3)caption
element (2)figure
li
elementfigure
element (2) (3) (4) (5) (6)figcaption
element (2)caption
elementstyle
element (2) (3)script
elementnoscript
elementbody
elementsection
element (2) (3)nav
element (2) (3)article
element (2) (3)aside
element (2) (3)h1
, h2
, h3
, h4
, h5
, and h6
elements (2)hgroup
element (2)header
element (2) (3)footer
element (2) (3)address
element (2) (3)p
element (2)hr
element (2)pre
element (2)blockquote
element (2) (3)ol
element (2)ul
element (2)li
elementdl
element (2)dd
elementfigure
element (2) (3) (4) (5) (6)figcaption
elementdiv
element (2) (3)a
element (2)em
elementstrong
elementsmall
elements
elementcite
elementq
elementdfn
elementabbr
elementtime
elementcode
elementvar
elementsamp
elementkbd
elementsub
and sup
elementsi
elementb
elementu
elementmark
elementruby
elementbdi
elementbdo
elementspan
elementbr
elementwbr
elementins
element (2)del
element (2)img
elementiframe
elementembed
elementobject
elementparam
elementvideo
elementaudio
elementsource
elementtrack
elementcanvas
elementmap
element (2)area
elementtable
element (2)caption
elementtd
elementform
element (2) (3)fieldset
element (2) (3)label
elementinput
elementbutton
elementselect
elementdatalist
elementtextarea
elementkeygen
elementoutput
elementprogress
elementmeter
elementdetails
element (2) (3)command
elementmenu
element (2) (3) (4)for
Document
as the label
element.label
element (2) (3) (4)for
for
attribute, if specified, must contain a string consisting of an unordered set of unique space-separated tokens that are case-sensitive, each of which must have the value of an ID of an element in the same Document
.output
element (2) (3) (4)for
script
elementsform
base
elementform
element (2) (3) (4) (5)legend
elementautocomplete
attributeoption
elementform
...
element, but may have a ... attribute specified to override this.object
element (2)fieldset
element (2)label
element (2)input
element (2)button
element (2)select
element (2)textarea
element (2)keygen
element (2)output
element (2)progress
elementmeter
element (2)dirname
attributedirname
attributetextarea
elementmaxlength
attributemaxlength
attributetextarea
elementobject
elementfieldset
elementlabel
elementinput
elementautocomplete
attributebutton
elementselect
elementtextarea
elementkeygen
elementoutput
elementmeter
elementobject
elementform
elementfieldset
elementlabel
elementinput
element (2)button
elementselect
elementtextarea
elementkeygen
elementoutput
elementprogress
elementmeter
elementformaction
action
and ... content attributes, if specified, must have a value that is a valid non-empty URL potentially surrounded by spaces.input
element (2) (3)button
element (2) (3)formAction
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The ... IDL attribute must reflect the ...
content attribute, except that on getting, when the content
attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.input
elementbutton
elementformatBlock
formatBlock
candidatesection
elementnav
elementarticle
elementaside
elementh1
, h2
, h3
, h4
, h5
, and h6
elementshgroup
elementheader
elementfooter
elementaddress
elementp
elementpre
elementblockquote
elementdiv
elementformenctype
enctype
and ... content attributes are enumerated attributes with the following keywords and states:input
element (2) (3)button
element (2) (3)formEnctype
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The ... IDL attribute must reflect the ...
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.input
elementbutton
elementformmethod
method
and ... content attributes are enumerated attributes with the following keywords and states:input
element (2) (3)button
element (2) (3)formMethod
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The ... IDL attribute must reflect the ...
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.input
elementbutton
elementformnovalidate
novalidate
and ... content attributes are boolean attributes. If present, they indicate that the form is not to be validated during submission.input
element (2) (3)button
element (2) (3) (4)formNoValidate
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The ... IDL attribute must reflect the ...
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.input
elementbutton
elementformtarget
target
and ... content attributes, if specified, must have values that are valid browsing context names or keywords.input
element (2) (3)button
element (2) (3)formTarget
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The ... IDL attribute must reflect the ...
content attribute.input
elementbutton
elementforwardDelete
frame
table
elementsframe
align
, ..., summary
, rules
, and width
, IDL attributes of the table
element must reflect the respective content attributes of the same name.frameborder
iframe
elementsframeBorder
frame
element must reflect the element's frameborder
content attribute.frameBorder
iframe
element must reflect the element's ...
content attribute.History
interfacebody
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20)TrackList
objectsWindow
object (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) (50) (51) (52) (53) (54) (55) (56) (57) (58) (59) (60) (61) (62) (63) (64) (65) (66) (67) (68) (69)DataTransferItem
interface (2)generator
get
html
elementhead
elementtitle
elementbase
elementlink
elementmeta
elementstyle
elementscript
elementnoscript
elementbody
elementsection
elementnav
elementarticle
elementaside
elementh1
, h2
, h3
, h4
, h5
, and h6
elementshgroup
elementheader
elementfooter
elementaddress
elementp
elementhr
elementpre
elementblockquote
elementol
elementul
elementli
elementdl
elementdt
elementdd
elementfigure
elementfigcaption
elementdiv
elementa
elementem
elementstrong
elementsmall
elements
elementcite
elementq
elementdfn
elementabbr
elementtime
elementcode
elementvar
elementsamp
elementkbd
elementsub
and sup
elementsi
elementb
elementu
elementmark
elementruby
elementrt
elementrp
elementbdi
elementbdo
elementspan
element (2)br
elementwbr
elementins
elementdel
elementimg
elementiframe
elementembed
elementobject
elementparam
elementvideo
elementaudio
elementsource
elementtrack
elementcanvas
elementmap
elementarea
elementtable
elementcaption
elementcolgroup
elementcol
elementtbody
elementthead
elementtfoot
elementtr
elementtd
elementth
elementform
elementfieldset
elementlegend
elementlabel
elementinput
elementbutton
elementselect
elementdatalist
elementoptgroup
elementoption
elementtextarea
elementkeygen
elementoutput
elementprogress
elementmeter
elementdetails
elementsummary
elementcommand
elementmenu
elementh1
section
elementh1
, h2
, h3
, h4
, h5
, and h6
elements (2) (3)hgroup
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)header
element (2) (3) (4)hr
elementb
element (2)canvas
elementh2
section
elementh1
, h2
, h3
, h4
, h5
, and h6
elements (2) (3)hgroup
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)header
element (2) (3) (4)hr
elementb
element (2)canvas
elementh3
section
elementh1
, h2
, h3
, h4
, h5
, and h6
elements (2) (3)hgroup
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)header
element (2) (3) (4)hr
elementb
element (2)canvas
elementh4
section
elementh1
, h2
, h3
, h4
, h5
, and h6
elements (2) (3)hgroup
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)header
element (2) (3) (4)hr
elementb
element (2)canvas
elementh5
section
elementh1
, h2
, h3
, h4
, h5
, and h6
elements (2) (3)hgroup
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)header
element (2) (3) (4)hr
elementb
element (2)canvas
elementh6
section
elementh1
, h2
, h3
, h4
, h5
, and h6
elements (2) (3)hgroup
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)header
element (2) (3) (4)hr
elementb
element (2)canvas
elementhard
wrap
attribute is an enumerated attribute with two keywords and states: the soft
keyword which maps to the Soft state, and the ... keyword which maps to the Hard state. The missing value default is the Soft state.textarea
elementtextarea
is to have newlines added by the user agent so that the text is wrapped when it is submitted.textarea
element (2) (3)min
and max
attributeshash
a
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, search
, and .... These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.a
element (2)hash
area
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, search
, and .... These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.area
element (2)hash
Location
interface also has the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, search
, and ....Location
interface (2)hashchange
HAVE_CURRENT_DATA
HAVE_ENOUGH_DATA
HAVE_FUTURE_DATA
HAVE_METADATA
HAVE_NOTHING
head
html
elementhead
element (2) (3)title
elementbase
elementlink
elementmeta
element (2) (3)style
elementnoscript
element (2) (3) (4) (5) (6) (7)header
article
elementheader
element (2) (3) (4) (5) (6) (7) (8) (9)footer
elementaddress
elementheaders
td
and th
element may have a ... content attribute specified. The headers
attribute, if specified, must contain a string consisting of an unordered set of unique space-separated tokens that are case-sensitive, each of which must have the value of an ID of a th
element taking part in the same table as the td
or th
element.td
elementth
elementtd
and th
elements (2) (3)headers
td
and th
elements (2)h1
, h2
, h3
, h4
, h5
, and h6
elementshgroup
element (2)address
elementh1
, h2
, h3
, h4
, h5
, and h6
elementshgroup
elementheight
canvas
element has two attributes to control the size of the coordinate space: width
and .... These attributes, when specified, must have values that are valid non-negative integers. The width
attribute defaults to 300, and the height
attribute defaults to 150.canvas
element (2) (3)height
width
and ... IDL attributes must reflect the respective content attributes of the same name, with the same defaults.canvas
element (2)height
width
and ... attributes on img
, iframe
, embed
, object
, video
, and, when their type
attribute is in the Image Button state, input
elements may be specified to give the dimensions of the visual content of the element (the width and height respectively, relative to the nominal direction of the output medium), in CSS pixels. The attributes, if specified, must have values that are valid
non-negative integers.img
element (2) (3)iframe
elementembed
elementobject
elementvideo
elementinput
element (2) (3)height
width
and ... IDL attributes on the iframe
, embed
, object
, and video
elements must reflect the respective content attributes of the same name.iframe
elementembed
elementobject
elementvideo
elementinput
elementheight
td
and th
elementsheight
align
, alt
, archive
, code
, ..., hspace
, name
, object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.height
behavior
, direction
, ..., hspace
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name.height
abbr
, align
, axis
, ..., and width
IDL attributes of the td
and th
elements must reflect the respective content attributes of the same name.hgroup
h1
, h2
, h3
, h4
, h5
, and h6
elementshgroup
element (2) (3) (4) (5) (6) (7) (8) (9) (10)header
elementHIERARCHY_REQUEST_ERR
table
element (2) (3)select
elementhigh
low
attribute specifies the range that is considered to be the "low" part, and the ... attribute specifies the range that is considered to be the "high" part. The optimum
attribute gives the position that is "optimum"; if that is higher than the "high" value then this indicates that the higher the value, the better; if it's lower than the "low" mark then it indicates that lower values are better, and naturally if it is in between then it indicates that neither high nor low values are good.meter
element (2) (3) (4) (5) (6) (7)high
min
, max
, low
, ..., and optimum
IDL attributes must reflect the respective content attributes of the same name.meter
element (2)history
Window
interface must return the object implementing the History
interface for that Window
object's Document
.Window
objectHistory
interface (2) (3) (4) (5) (6) (7)Location
interfaceWindow
objectHistory
interface (2) (3) (4)host
a
element also supports the complement of URL decomposition IDL attributes, protocol
, ..., port
, hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.a
element (2)host
area
element also supports the complement of URL decomposition IDL attributes, protocol
, ..., port
, hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.area
element (2)host
Location
interface also has the complement of URL decomposition IDL attributes, protocol
, ..., port
, hostname
, pathname
, search
, and hash
.Location
interface (2)hostname
a
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, ..., pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.a
element (2)hostname
area
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, ..., pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.area
element (2)hostname
Location
interface also has the complement of URL decomposition IDL attributes, protocol
, host
, port
, ..., pathname
, search
, and hash
.Location
interface (2)hr
hr
element (2) (3) (4) (5) (6)href
base
element (2) (3) (4) (5)href
...
content attribute to the given new value.base
element (2)href
link
element (2)href
rel
, media
, hreflang
, and type
, and sizes
each must reflect the respective content attributes of the same name.link
element (2)href
target
, rel
, media
, hreflang
, and type
, must reflect the respective content attributes of the same name.a
element (2)href
alt
, coords
, ..., target
, rel
, media
, hreflang
, and type
, each must reflect the respective content attributes of the same name.area
element (2)href
a
and area
elements must have a value that is a valid URL potentially surrounded by spaces.a
element (2) (3) (4) (5) (6)img
element (2)area
element (2) (3) (4) (5) (6)a
and area
elements (2) (3)hidden
attributehreflang
link
element has the same semantics as the hreflang
attribute on a
and area
elements.link
element (2)hreflang
href
, rel
, media
, ..., and type
, and sizes
each must reflect the respective content attributes of the same name.link
element (2)hreflang
href
, target
, rel
, media
, ..., and type
, must reflect the respective content attributes of the same name.a
element (2)hreflang
alt
, coords
, href
, target
, rel
, media
, ..., and type
, each must reflect the respective content attributes of the same name.area
element (2)hreflang
a
and area
elements that create hyperlinks, if present, gives the language of the linked resource. It is purely advisory. The value must be a valid BCP 47 language tag. [BCP47]link
elementa
element (2)area
element (2)a
and area
elementsalternate
" (2) (3)hspace
embed
elementsembed
elementhspace
iframe
elementshspace
input
elementshspace
img
elementshspace
object
elementshspace
align
, alt
, archive
, code
, height
, ..., name
, object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.hspace
behavior
, direction
, height
, ..., vspace
, and width
IDL attributes must reflect the respective content attributes of the same name.hspace
name
, align
, border
, ..., and vspace
IDL attributes of the img
element must reflect the respective content attributes of the same name.hspace
align
, archive
, border
, code
, declare
, ..., standby
, and vspace
IDL attributes of the object
element must reflect the respective content attributes of the same name.html
html
element (2) (3)head
elementbase
elementbody
element (2) (3)iframe
elementlang
and xml:lang
attributes (2)xml:base
attribute (XML only)data-*
attributesnoscript
element (2) (3)iframe
element (2)embed
elementtext/html
text/html-sandboxed
title
attributelang
and xml:lang
attributes (2) (3) (4)class
attributestyle
attributedata-*
attributes (2)body
elementhidden
attributeaccesskey
attributedraggable
attributedropzone
attributeapplication/xhtml+xml
(2)a
elementarea
elementaudio
elementbase
elementbody
elementbr
elementcanvas
elementmap
element (2) (3) (4)table
element (2) (3) (4)tbody
element (2)tr
element (2)form
elementselect
element (2)datalist
element (2)command
elementdatalist
elementdetails
elementdiv
elementdl
elementdir
attributehtml
elementhead
elementtitle
elementbase
elementlink
elementmeta
elementstyle
elementscript
elementnoscript
elementbody
elementsection
elementnav
elementarticle
elementaside
elementh1
, h2
, h3
, h4
, h5
, and h6
elementshgroup
elementheader
elementfooter
elementaddress
elementp
elementhr
elementpre
elementblockquote
elementol
elementul
elementli
elementdl
elementdt
elementdd
elementfigure
elementfigcaption
elementdiv
elementa
elementem
elementstrong
elementsmall
elements
elementcite
elementdfn
elementabbr
elementtime
elementcode
elementvar
elementsamp
elementkbd
elementsub
and sup
elementsi
elementb
elementu
elementmark
elementruby
elementrt
elementrp
elementbdi
elementbdo
elementspan
elementbr
elementwbr
elementins
and del
elementsimg
elementiframe
elementembed
elementobject
elementparam
elementsource
elementtrack
elementcanvas
elementmap
elementarea
elementtable
element (2) (3) (4) (5) (6)caption
elementcolgroup
elementtbody
element (2)tr
element (2)td
and th
elementsform
elementfieldset
elementlegend
elementlabel
element (2)input
element (2)button
elementselect
element (2) (3) (4)datalist
elementoptgroup
elementoption
elementtextarea
elementkeygen
elementoutput
elementprogress
elementmeter
elementdetails
elementsummary
elementcommand
elementmenu
elementembed
elementfieldset
elementhtmlFor
for
content attribute.label
element (2)htmlFor
for
content attribute.output
element (2)form
elementfieldset
element (2)object
elementform
elementfieldset
elementlegend
elementlabel
elementinput
elementbutton
elementselect
elementoption
elementtextarea
elementkeygen
elementoutput
elementprogress
elementmeter
elementhead
elementh1
, h2
, h3
, h4
, h5
, and h6
elementshr
elementhtml
elementiframe
elementimg
element (2) (3)input
elementkeygen
elementlabel
elementlegend
elementli
elementlink
element (2)map
elementvideo
elementaudio
elementmeta
elementmeter
elementins
elementdel
elementins
and del
elements (2)object
elementol
elementoptgroup
elementinput
elementoption
elementselect
element (2)output
elementp
elementparam
elementpre
elementprogress
elementblockquote
element (2)q
elementscript
elementselect
elementsource
elementspan
elementstyle
element (2)table
elementcaption
elementtd
elementth
elementtd
and th
elements (2)colgroup
elementcol
elementtd
elementtable
elementth
elementtr
elementtable
element (2)tbody
element (2)thead
elementtfoot
elementtextarea
elementtime
elementtitle
elementtrack
elementul
elementvideo
elementhttp-equiv
meta
element (2) (3) (4) (5) (6) (7) (8)httpEquiv
meta
element (2)nofollow
"noreferrer
"base
element (2)link
element (2)a
elementarea
elementa
and area
elementsalternate
" (2)author
"bookmark
"external
"help
"license
"nofollow
"noreferrer
"search
"sidebar
" (2)tag
"next
"prev
"i
em
elementi
element (2) (3) (4) (5) (6) (7) (8)b
elementu
elementicon
command
element (2)icon
label
, ..., disabled
, checked
, and radiogroup
IDL attributes must reflect the respective content attributes of the same name.command
element (2)id
id
attribute (2) (3)map
elementid
...
content attribute.id
attributeiframe
iframe
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31)image
input
elementimg
elementobject
elementmap
elementarea
element (2) (3)Image()
img
element (2) (3)Image(width)
img
element (2)Image(width, height)
img
element (2)img
img
element (2) (3) (4) (5) (6) (7)map
elementtext/html
Document
indeterminate
input
element (2)INDEX_SIZE_ERR
table
element (2)tbody
element (2)tr
element (2)initDragEvent()
DragEvent
interface (2)initHashChangeEvent()
initPageTransitionEvent()
initPopStateEvent()
script
elementscript
elementsinnerHTML
innerHTML
(2) (3) (4)script
elementnoscript
elementinput
title
attributeform
element (2)input
element (2) (3) (4) (5) (6)input
element attributeslist
attributemaxlength
attributepattern
attributeinput
element APIsdatalist
element (2)ins
ins
element (2) (3) (4)ins
and del
elements (2)insertHTML
insertImage
insertLineBreak
insertOrderedList
insertParagraph
insertText
insertUnorderedList
style
elementa
element (2)img
elementiframe
elementembed
elementobject
elementvideo
elementaudio
elementlabel
elementinput
elementbutton
element (2)select
elementtextarea
elementkeygen
elementdetails
elementmenu
elementINUSE_ATTRIBUTE_ERR
INVALID_ACCESS_ERR
INVALID_CHARACTER_ERR
INVALID_MODIFICATION_ERR
INVALID_STATE_ERR
document.write()
document.writeln()
innerHTML
(2)outerHTML
input
element APIs (2) (3) (4)isindex
isindex
ismap
a
element with an href
attribute, indicates by its presence that the element provides access to a server-side image map. This affects how events are handled on the corresponding a
element.img
element (2) (3)isMap
alt
, src
, useMap
, and ... each must reflect the respective content attributes of the same name.img
element (2)italic
kbd
pre
element (2)samp
element (2)kbd
element (2) (3) (4) (5) (6) (7) (8) (9)keygen
keygen
element (2) (3)keytype
keygen
element (2)keytype
keygen
element (2)keywords
kind
track
element (2) (3) (4)kind
src
, srclang
, label
, and default
IDL attributes must reflect the respective content attributes of the same name. The ... IDL attribute must reflect the content attribute of the same name, limited to only known values.track
element (2)label
track
element (2) (3) (4)label
src
, srclang
, ..., and default
IDL attributes must reflect the respective content attributes of the same name. The kind
IDL attribute must reflect the content attribute of the same name, limited to only known values.track
element (2)label
label
element (2) (3) (4) (5) (6) (7)placeholder
attributetextarea
elementlabel
disabled
and ... attributes must reflect the respective content attributes of the same name.optgroup
element (2)label
option
element is the value of the label
attribute, if there is one, or the textContent
of the element, if there isn't.option
element (2) (3)option
element is the value of the ...
attribute, if there is one, or the textContent
of the element, if there isn't.datalist
elementoption
elementlabel
disabled
and ... IDL attributes must reflect the respective content attributes of the same name. The defaultSelected
IDL attribute must reflect the selected
content attribute.option
element (2)label
label
attribute must be specified and must have a value that is not the empty string.command
element (2) (3)label
icon
, disabled
, checked
, and radiogroup
IDL attributes must reflect the respective content attributes of the same name.command
element (2)label
element (2)input
elementbutton
elementselect
elementtextarea
elementkeygen
elementoutput
elementprogress
elementmeter
elementlang
lang
and xml:lang
attributes (2) (3) (4) (5) (6)div
elementi
elementspan
elementlang
lang
and xml:lang
attributes (2) (3) (4) (5) (6)i
elementlang
...
content attribute in no namespace.lang
and xml:lang
attributeslegend
fieldset
element (2) (3)legend
element (2) (3)li
ol
element (2)ul
element (2)li
element (2) (3) (4) (5) (6)menu
element (2) (3)link
title
attributelink
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)meta
elementstyle
elementnoscript
element (2) (3)alternate
" (2)author
" (2)help
" (2)icon
"license
"pingback
"prefetch
"search
" (2)sidebar
"stylesheet
" (2) (3)tag
"next
"prev
"link
body
elementslink
body
element must reflect the element's ...
content attribute.link
element (2) (3)icon
"pingback
"prefetch
"stylesheet
"list
input
element (2) (3)list
attribute (2)input
element APIs (2)datalist
elementtype
attribute is an enumerated attribute indicating the kind of menu being declared. The attribute has three states. The context
keyword maps to the context menu state, in which the element is declaring a context menu. The toolbar
keyword maps to the toolbar state, in which the element is declaring a toolbar. The attribute may also be omitted. The missing value default is the ... state, which indicates that the element is merely a list of commands that is neither declaring a context menu nor defining a toolbar.menu
element (2)object
elementfieldset
elementinput
element (2)button
elementselect
elementtextarea
elementkeygen
elementoutput
elementlisting
loadeddata
loadeddata
loadedmetadata
loadedmetadata
loadstart
input
element (2)Window
objectLocation
interface (2) (3) (4) (5) (6)longdesc
iframe
elementslongdesc
img
elementslongDesc
frame
element must reflect the element's longdesc
content attribute, which for the purposes of reflection is defined as containing a URL.longDesc
iframe
element must reflect the element's ...
content attribute, which for the purposes of reflection is defined as containing a URL.longDesc
img
element must reflect the element's ...
content attribute, which for the purposes of reflection is defined as containing a URL.loop
video
element (2)audio
element (2)loop
low
high
attribute specifies the range that is considered to be the "high" part. The optimum
attribute gives the position that is "optimum"; if that is higher than the "high" value then this indicates that the higher the value, the better; if it's lower than the "low" mark then it indicates that lower values are better, and naturally if it is in between then it indicates that neither high nor low values are good.meter
element (2) (3) (4) (5) (6) (7)low
min
, max
, ..., high
, and optimum
IDL attributes must reflect the respective content attributes of the same name.meter
element (2)ol
elementol
elementlowsrc
ltr
dir
attributedir
attribute (2)dir
attribute (2) (3) (4)bdo
elementmap
map
element (2) (3) (4) (5)area
elementmarginbottom
marginheight
body
elementsmarginheight
iframe
elementsmarginHeight
frame
element must reflect the element's marginheight
content attribute.marginHeight
iframe
element must reflect the element's ...
content attribute.marginleft
marginright
margintop
marginwidth
body
elementsmarginwidth
iframe
elementsmarginWidth
frame
element must reflect the element's marginwidth
content attribute.marginWidth
iframe
element must reflect the element's ...
content attribute.mark
b
elementu
elementmark
element (2) (3) (4) (5) (6) (7) (8)math
max
accept
, alt
, ..., min
, multiple
, pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)max
min
and ... attributes indicate the allowed range of values for the element.input
element (2) (3)min
and max
attributes (2) (3)max
value
attribute specifies how much of the task has been completed, and the ... attribute specifies how much work the task requires in total. The units are arbitrary and not specified.progress
element (2) (3) (4) (5) (6) (7)max
max
is 1.0.progress
element (2) (3)max
min
attribute specifies the lower bound of the range, and the ... attribute specifies the upper bound. The value
attribute specifies the value to have the gauge indicate as the "measured" value.meter
element (2) (3) (4)max
min
, ..., low
, high
, and optimum
IDL attributes must reflect the respective content attributes of the same name.meter
element (2)maxlength
attribute (2)textarea
element (2)maxLength
autocomplete
and type
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The ... IDL attribute must reflect the maxlength
content attribute, limited to only
non-negative numbers.input
element (2)maxlength
maxlength
attribute.input
element (2) (3) (4)maxlength
attribute (2)maxlength
maxlength
attribute controlled by the textarea
element's dirty value flag.textarea
element (2) (3) (4)maxLength
cols
, placeholder
, required
, rows
, and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The ... IDL attribute must reflect the ...
content attribute, limited to only non-negative numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.textarea
element (2)media
link
element (2) (3) (4)media
href
, rel
, ..., hreflang
, and type
, and sizes
each must reflect the respective content attributes of the same name.link
element (2)media
style
element (2) (3)media
type
and scoped
IDL attributes must reflect the respective content attributes of the same name.style
element (2)media
href
, target
, rel
, ..., hreflang
, and type
, must reflect the respective content attributes of the same name.a
element (2)media
source
element (2)media
src
, type
, and ... must reflect the respective content attributes of the same name.source
element (2)media
alt
, coords
, href
, target
, rel
, ..., hreflang
, and type
, each must reflect the respective content attributes of the same name.area
element (2)media
media
attribute is omitted, is "all
".a
element (2)area
element (2)a
and area
elements (2)alternate
" (2) (3)video
elementaudio
elementvideo
elementaudio
elementvideo
element (2) (3)audio
element (2) (3)source
element (2) (3) (4)track
element (2) (3)source
element (2) (3) (4) (5) (6) (7)track
element (2) (3)MEDIA_ERR_ABORTED
MEDIA_ERR_DECODE
MEDIA_ERR_NETWORK
MEDIA_ERR_SRC_NOT_SUPPORTED
mediagroup
MediaController
.video
element (2)audio
element (2)mediaGroup
...
content attribute.meta
meta
element (2) (3) (4) (5) (6) (7) (8)noscript
element (2) (3)metadata
track
elementtrack
elementmetadata
head
element (2)title
elementbase
elementlink
element (2)meta
element (2)style
element (2)script
element (2)noscript
elementcommand
element (2)meter
progress
elementmeter
element (2) (3) (4) (5) (6) (7) (8)method
formmethod
content attributes are enumerated attributes with the following keywords and states:form
element (2)formmethod
attribute, then the element's method is that attribute's state; otherwise, it is the form owner's ...
attribute's state.method
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The ... and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.form
elementmethods
a
elementsmethods
link
elementslink
elementembed
elementinput
elementa
and area
elementsmin
accept
, alt
, max
, ..., multiple
, pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)min
max
attributes indicate the allowed range of values for the element.input
element (2) (3)min
and max
attributes (2) (3)min
max
attribute specifies the upper bound. The value
attribute specifies the value to have the gauge indicate as the "measured" value.meter
element (2) (3) (4)min
max
, low
, high
, and optimum
IDL attributes must reflect the respective content attributes of the same name.meter
element (2)month
input
elementmulticol
multipart/form-data
multiple
accept
, alt
, max
, min
, ..., pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)multiple
input
element (2) (3) (4)multiple
attribute (2)pattern
attributemultiple
select
element represents a control for selecting zero or more options from the list of options. If the attribute is absent, then the select
element represents a control for selecting a single option from the list of options.select
element (2) (3) (4) (5) (6) (7)option
elementmultiple
required
, and size
IDL attributes must reflect the respective content attributes of the same name. The size
IDL attribute is limited to only non-negative numbers, with the default value zero (which for historical reasons is different from the default value of the size
content attribute that it reflects).select
element (2)TrackList
objects (2)muted
video
element (2)audio
element (2)name
meta
element has a ... attribute, it sets document metadata. Document metadata is expressed in terms of name/value pairs, the name
attribute on the meta
element giving the name, and the content
attribute on the same element giving the value. The name specifies what aspect of metadata is being set; valid names and the meaning of their values are described in the following sections. If a meta
element has no content
attribute, then the value part of the metadata name/value pair is the empty string.meta
element (2) (3) (4) (5) (6) (7)name
content
IDL attributes must reflect the respective content attributes of the same name. The IDL attribute httpEquiv
must reflect the content attribute http-equiv
.meta
element (2)name
iframe
element (2)name
src
, srcdoc
, ..., sandbox
, and seamless
must reflect the respective content attributes of the same name.iframe
element (2)name
object
element (2)name
data
, type
, ..., and useMap
each must reflect the respective content attributes of the same name.object
element (2)name
value
must both reflect the respective content attributes of the same name.param
element (2)name
name
attribute must not be a compatibility-caseless match for the value of the name
attribute of another map
element in the same document. If the id
attribute is also specified, both attributes must have the same value.map
element (2) (3) (4)name
map
element (2)name
form
's name within the forms
collection. The value must not be the empty string, and the value must be unique amongst the form
elements in the forms
collection that it is in, if any.form
element (2)name
form
element (2)name
form
element's elements
object. If the attribute is specified, its value must not be the empty string.form
element (2) (3)fieldset
element (2)input
element (2)button
element (2)select
element (2)textarea
element (2)keygen
element (2)output
element (2)name
...
content attribute.fieldset
elementinput
elementbutton
elementselect
elementtextarea
elementkeygen
elementoutput
elementname
a
elements (except as noted in the previous section)name
embed
elementsembed
elementname
img
elementsname
option
elementsselect
elementname
align
, alt
, archive
, code
, height
, hspace
, ..., object
, vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.name
scrolling
, and src
IDL attributes of the frame
element must reflect the respective content attributes of the same name.name
coords
, charset
, ..., rev
, and shape
IDL attributes of the a
element must reflect the respective content attributes of the same name.name
align
IDL attributes of the embed
element must reflect the respective content attributes of the same name.name
align
, border
, hspace
, and vspace
IDL attributes of the img
element must reflect the respective content attributes of the same name.NAMESPACE_ERR
time
element (2) (3) (4) (5)iframe
element (2) (3) (4) (5) (6) (7)object
element (2) (3) (4)NETWORK_EMPTY
NETWORK_ERR
NETWORK_LOADING
NETWORK_NO_SOURCE
nextid
NO_DATA_ALLOWED_ERR
NO_MODIFICATION_ALLOWED_ERR
outerHTML
insertAdjacentHTML()
noembed
noframes
nohref
area
elementsnoHref
area
element must reflect the element's ...
content attribute.noResize
noscript
link
elementmeta
elementstyle
elementnoscript
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33)noshade
hr
elementsnoShade
hr
element must reflect the element's noshade
content attribute.NOT_FOUND_ERR
NOT_SUPPORTED_ERR
noupdate
novalidate
formnovalidate
content attributes are boolean attributes. If present, they indicate that the form is not to be validated during submission.form
element (2)noValidate
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The target
IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The ... IDL attribute must reflect the ...
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content
attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.form
elementnowrap
td
and th
elementsnoWrap
td
and th
elements must reflect the elements' ...
content attributes.number
input
elementobject
embed
elementobject
element (2) (3) (4) (5) (6) (7) (8) (9)param
element (2)map
elementobject
align
, alt
, archive
, code
, height
, hspace
, name
, ..., vspace
, and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.obsolete
OBSOLETE
autocomplete
attribute is an enumerated attribute. The attribute has two states. The on
keyword maps to the on state, and the off
keyword maps to the ... state. The attribute may also be omitted. The missing value default is the on state. The off state indicates that by default, input
elements in the form will have their resulting autocompletion state set to off; the on state indicates that by default, input
elements in the form will have their resulting autocompletion state set to on.form
element (2)autocomplete
attribute is an enumerated attribute. The attribute has three states. The on
keyword maps to the on state, and the off
keyword maps to the ... state. The attribute may also be omitted. The missing value default is the default state.autocomplete
attribute (2)ol
ol
element (2) (3) (4)ul
element (2)li
element (2) (3) (4) (5)autocomplete
attribute is an enumerated attribute. The attribute has two states. The on
keyword maps to the ... state, and the off
keyword maps to the off state. The attribute may also be omitted. The missing value default is the on state. The off state indicates that by default, input
elements in the form will have their resulting autocompletion state set to off; the on state indicates that by default, input
elements in the form will have their resulting autocompletion state set to on.form
element (2) (3)autocomplete
attributeautocomplete
attribute is an enumerated attribute. The attribute has three states. The on
keyword maps to the ... state, and the off
keyword maps to the off state. The attribute may also be omitted. The missing value default is the default state.autocomplete
attribute (2)open
details
element (2) (3)open
...
content attribute.details
element (2)open()
document.write()
document.writeln()
optgroup
select
element (2) (3) (4)optgroup
element (2) (3)option
element (2)optimum
low
attribute specifies the range that is considered to be the "low" part, and the high
attribute specifies the range that is considered to be the "high" part. The ... attribute gives the position that is "optimum"; if that is higher than the "high" value then this indicates that the higher the value, the better; if it's lower than the "low" mark then it indicates that lower values are better, and naturally if it is in between then it indicates that neither high nor low values are good.meter
element (2) (3) (4) (5)optimum
min
, max
, low
, high
, and ... IDL attributes must reflect the respective content attributes of the same name.meter
element (2)option
list
attribute (2)input
element APIsselect
element (2) (3) (4) (5) (6) (7) (8) (9)datalist
element (2) (3) (4)optgroup
element (2) (3) (4) (5)option
element (2) (3) (4) (5) (6) (7) (8)form
elementaccesskey
attributeol
elementli
element (2)section
elementhgroup
elementheader
elementhr
elementoutput
output
element (2) (3) (4)p
dir
attributeaddress
elementp
element (2) (3)blockquote
elementpagehide
pageshow
p
elementhr
elementdfn
elementbr
elementins
element (2)del
elementparam
object
elementparam
element (2) (3)password
input
elementpathname
a
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, ..., search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.a
element (2)pathname
area
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, ..., search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.area
element (2)pathname
Location
interface also has the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, ..., search
, and hash
.Location
interface (2)pattern
accept
, alt
, max
, min
, multiple
, ..., placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)pattern
multiple
attribute applies and is set, the control's values, are to be checked.input
element (2) (3)pattern
attribute (2) (3) (4)pause
script
element (2)noscript
element (2)h1
, h2
, h3
, h4
, h5
, and h6
elementsp
elementpre
elementdt
elementa
element (2) (3) (4)em
element (2) (3)strong
element (2) (3)small
element (2) (3)s
element (2) (3)cite
element (2) (3)q
element (2) (3) (4)dfn
element (2) (3)abbr
element (2) (3)time
element (2) (3)code
element (2) (3)var
element (2) (3)samp
element (2) (3)kbd
element (2) (3)sub
and sup
elements (2) (3)i
element (2) (3)b
element (2) (3)u
element (2) (3)mark
element (2) (3)ruby
element (2) (3)rt
elementrp
elementbdi
element (2) (3)bdo
element (2) (3)span
element (2) (3)br
element (2)wbr
element (2)ins
element (2) (3) (4) (5)del
element (2) (3) (4)img
elementiframe
element (2)embed
elementobject
elementvideo
elementaudio
elementcanvas
elementmap
element (2) (3) (4)area
element (2)th
elementlegend
elementlabel
element (2) (3)input
element (2)button
element (2) (3)select
element (2)datalist
element (2) (3)textarea
element (2)keygen
element (2)output
element (2) (3)progress
element (2) (3)meter
element (2) (3)summary
elementcommand
element (2)placeholder
accept
, alt
, max
, min
, multiple
, pattern
, ..., required
, size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)placeholder
input
element (2) (3)placeholder
attribute (2) (3) (4)placeholder
textarea
element (2) (3)placeholder
cols
, ..., required
, rows
, and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The
cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative
numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.textarea
element (2)select
element (2)option
element (2)plaintext
playing
playing
embed
element (2)object
elementarea
element (2)port
a
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, ..., hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.a
element (2)port
area
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, ..., hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.area
element (2)port
Location
interface also has the complement of URL decomposition IDL attributes, protocol
, host
, ..., hostname
, pathname
, search
, and hash
.Location
interface (2)post
poster
video
element (2) (3) (4)poster
...
content attribute.video
element (2)pre
dir
attributepre
element (2) (3) (4) (5) (6) (7) (8) (9)code
element (2)samp
elementscript
elementform
elementtext/html
preload
video
element (2)audio
element (2)preload
profile
progress
progress
progress
element (2) (3) (4) (5)meter
elementprogress
protocol
a
element also supports the complement of URL decomposition IDL attributes, ..., host
, port
, hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.a
element (2)protocol
area
element also supports the complement of URL decomposition IDL attributes, ..., host
, port
, hostname
, pathname
, search
, and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.area
element (2)protocol
Location
interface also has the complement of URL decomposition IDL attributes, ..., host
, port
, hostname
, pathname
, search
, and hash
.Location
interface (2)pubdate
article
element, or, if the element has no ancestor article
element, of the document as a whole. If the element has a pubdate
attribute specified, then the element needs a date. For each article
element, there must be no more than one time
element with a pubdate
attribute whose nearest ancestor is that article
element. Furthermore, for each Document
, there must be no more than one time
element with a pubdate
attribute that does not have an ancestor article
element.article
elementtime
element (2) (3) (4) (5) (6)pubDate
...
content attribute.time
element (2)q
blockquote
elementcite
elementq
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)QUOTA_EXCEEDED_ERR
radio
input
elementradio
command
" keyword maps to the Command state, the "checkbox
" keyword maps to the Checkbox state, and the "..." keyword maps to the Radio state. The missing value default is the Command state.command
elementcommand
element (2) (3) (4)radiogroup
type
attribute has the value "radio
". The scope of the name is the child list of the parent element. The attribute must be omitted unless the type
attribute is in the Radio state.command
element (2)radiogroup
label
, icon
, disabled
, checked
, and ... IDL attributes must reflect the respective content attributes of the same name.command
element (2)range
input
elementh1
, h2
, h3
, h4
, h5
, and h6
elementshgroup
element (2) (3)ratechange
ratechange
readOnly
accept
, alt
, max
, min
, multiple
, pattern
, placeholder
, required
, size
, src
, and step
IDL attributes must reflect the respective
content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The ... IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)readonly
input
element (2) (3) (4)readonly
attribute (2)readonly
textarea
element (2) (3)readOnly
cols
, placeholder
, required
, rows
, and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative numbers. The ... IDL attribute must reflect the ...
content attribute.textarea
element (2)area
element (2) (3)redo
id
attributetitle
attributelang
and xml:lang
attributesdir
attribute (2)class
attributebase
elementlink
element (2)meta
element (2)style
elementscript
element (2)blockquote
elementol
elementli
elementa
element (2)time
element (2)ins
and del
elements (2)img
element (2)iframe
elementembed
elementobject
elementparam
elementvideo
elementsource
elementtrack
element (2)canvas
elementmap
elementarea
element (2) (3)table
elementcolgroup
elementcol
elementth
elementtd
and th
elements (2) (3)form
element (2) (3)fieldset
elementlabel
elementinput
element (2) (3) (4) (5) (6) (7)button
element (2)select
elementoptgroup
elementoption
element (2)textarea
element (2) (3) (4)keygen
element (2)output
elementprogress
elementmeter
elementdetails
elementcommand
element (2)menu
elementhidden
attributetabindex
attributeaccesskey
attributedropzone
attributerel
link
element (2) (3) (4) (5) (6) (7) (8)alternate
"rel
href
, ..., media
, hreflang
, and type
, and sizes
each must reflect the respective content attributes of the same name.link
element (2)rel
href
, target
, ..., media
, hreflang
, and type
, must reflect the respective content attributes of the same name.a
element (2)rel
alt
, coords
, href
, target
, ..., media
, hreflang
, and type
, each must reflect the respective content attributes of the same name.area
element (2)rel
a
and area
elements controls what kinds of links the elements create. The attribue's value must be a set of space-separated tokens. The allowed keywords and their meanings are defined below.link
elementa
element (2) (3)area
element (2) (3)a
and area
elements (2)relList
rel
content attribute.link
element (2)relList
rel
content attribute.a
element (2)relList
rel
content attribute.area
element (2)required
accept
, alt
, max
, min
, multiple
, pattern
, placeholder
, ..., size
, src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)required
input
element (2) (3)required
attribute (2)required
attributerequired
select
element (2) (3) (4)required
multiple
, ..., and size
IDL attributes must reflect the respective content attributes of the same name. The size
IDL attribute is limited to only non-negative numbers, with the default value zero (which for historical reasons is different from the default value of the size
content attribute that it reflects).select
element (2)required
textarea
element (2)required
cols
, placeholder
, ..., rows
, and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The
cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative
numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.textarea
element (2)reset
input
elementinput
element (2)select
elementtextarea
elementkeygen
elementoutput
elementscript
elementsscript
element (2)script
elementsrev
a
elementsrev
link
elementsrev
coords
, charset
, name
, ..., and shape
IDL attributes of the a
element must reflect the respective content attributes of the same name.rev
charset
, ..., and target
IDL attributes of the link
element must reflect the respective content attributes of the same name.reversed
ol
element (2)li
elementreversed
start
, and type
IDL attributes must reflect the respective content attributes of the same name. The start
IDL attribute has the same default as its content attribute.ol
element (2)dir
attributealternate
"Document
objectrowgroup
th
element (2) (3)rows
rows
attribute is specified, its value must be a valid non-negative integer greater than zero.textarea
element (2) (3)rows
cols
, placeholder
, required
, ..., and wrap
attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The
cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative
numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.textarea
element (2) (3) (4)rows
cols
and ... IDL attributes of the frameset
element must reflect the respective content attributes of the same name.rowspan
td
and th
elements may also have a ... content attribute specified, whose value must be a valid non-negative integer.td
elementth
elementtd
and th
elementsrowSpan
td
and th
elements (2)rp
ruby
element (2) (3)rt
elementrp
element (2) (3) (4)rt
ruby
element (2) (3) (4)rt
element (2) (3)rp
elementrtl
dir
attributedir
attribute (2)dir
attribute (2) (3)bdo
elementruby
u
elementruby
element (2) (3)rt
element (2)rp
elementrules
table
elementsrules
align
, frame
, summary
, ..., and width
, IDL attributes of the table
element must reflect the respective content attributes of the same name.s
s
element (2) (3)samp
pre
element (2)samp
element (2) (3) (4)kbd
element (2) (3)sandbox
iframe
. Its value must be an unordered set of unique space-separated tokens that are ASCII case-insensitive. The allowed values are allow-same-origin
, allow-top-navigation
, allow-forms
, and allow-scripts
. When the attribute is set, the content is treated as being from a unique origin, forms and scripts are disabled, links are prevented from targeting other browsing contexts, and plugins are disabled. The allow-same-origin
keyword allows the content to be treated as being from the same origin instead of forcing it into a unique origin, the allow-top-navigation
keyword allows the content to navigate its top-level browsing context,
and the allow-forms
and allow-scripts
keywords re-enable forms and scripts respectively (though scripts are still prevented from creating popups).iframe
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)sandbox
src
, srcdoc
, name
, ..., and seamless
must reflect the respective content attributes of the same name.iframe
element (2)scheme
meta
elementsscheme
meta
element must reflect the content attribute of the same name.scope
th
element may have a ... content attribute specified. The scope
attribute is an enumerated attribute with five states, four of which have explicit keywords:th
element (2) (3) (4) (5) (6) (7) (8)scope
th
element (2)scoped
style
element's parent element, as opposed to the whole Document
.style
element (2) (3) (4) (5) (6)scoped
media
, type
and ... IDL attributes must reflect the respective content attributes of the same name.style
element (2)script
dir
attributemeta
elementscript
element (2) (3) (4) (5) (6) (7) (8)script
elements (2)noscript
element (2)iframe
elementscrollAmount
scrollDelay
scrolling
iframe
elementsscrolling
name
, ..., and src
IDL attributes of the frame
element must reflect the respective content attributes of the same name.scrolling
align
and ... IDL attributes of the iframe
element must reflect the respective content attributes of the same name.seamless
iframe
element's browsing context is to be rendered in a manner that makes it appear to be part of the containing document (seamlessly included in the parent document).iframe
element (2) (3)seamless
src
, srcdoc
, name
, sandbox
, and ... must reflect the respective content attributes of the same name.iframe
element (2)search
a
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, ..., and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.a
element (2)search
area
element also supports the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, ..., and hash
. These must follow the rules given for URL decomposition IDL attributes, with the input being the result of resolving the element's href
attribute relative to the element, if there is such an attribute and resolving it is successful, or the empty string otherwise; and the common setter action being the same as setting the element's href
attribute to the new output value.area
element (2)search
input
elementinput
element (2) (3) (4) (5)search
Location
interface also has the complement of URL decomposition IDL attributes, protocol
, host
, port
, hostname
, pathname
, ..., and hash
.Location
interface (2)sidebar
"section
section
element (2) (3) (4) (5) (6)hr
elementdiv
element...
elements, though some may correspond to such elements — they are merely conceptual sections.)section
elementnav
elementarticle
elementaside
elementheader
elementfooter
element (2) (3)address
elementdfn
elementbody
elementfooter
element (2)blockquote
elementfigure
elementtd
elementfieldset
elementdetails
elementSECURITY_ERR
seeking
select
list
attributeselect
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17)optgroup
element (2)option
element (2) (3) (4) (5) (6) (7)selectAll
selected
list
attributeoption
element (2) (3) (4) (5)input
element APIsHistory
interface (2) (3) (4) (5)History
interfaceclass
attributelink
elementa
and area
elementsshape
area
element (2) (3) (4) (5)shape
...
content attribute.area
element (2)shape
a
elementsshape
coords
, charset
, name
, rev
, and ... IDL attributes of the a
element must reflect the respective content attributes of the same name.sidebar
"size
accept
, alt
, max
, min
, multiple
, pattern
, placeholder
, required
, ..., src
, and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)size
input
element (2) (3)size
attribute (2) (3)select
element (2) (3)size
...
attribute, if specified, must have a value that is a valid non-negative integer greater than zero. If the multiple
attribute is present, then the ...
attribute's default value is 4. If the multiple
attribute is absent, then the ...
attribute's default value is 1.select
element (2) (3)size
multiple
, required
, and ... IDL attributes must reflect the respective content attributes of the same name. The size
IDL attribute is limited to only non-negative numbers, with the default value zero (which for historical reasons is different from the default value of the ...
content attribute that it reflects).select
element (2) (3)size
hr
elementssize
color
, face
, and ... IDL attributes of the basefont
element must reflect the respective content attributes of the same name.size
color
, face
, and ... IDL attributes of the font
element must reflect the respective content attributes of the same name.size
align
, color
, ..., and width
IDL attributes of the hr
element must reflect the respective content attributes of the same name.sizes
href
, rel
, media
, hreflang
, and type
, and ... each must reflect the respective content attributes of the same name.link
element (2)small
small
element (2) (3) (4) (5) (6) (7) (8)soft
wrap
attribute is an enumerated attribute with two keywords and states: the ... keyword which maps to the Soft state, and the hard
keyword which maps to the Hard state. The missing value default is the Soft state.textarea
elementtextarea
is not to be wrapped when it is submitted (though it can still be wrapped in the rendering).textarea
element (2) (3)source
video
elementaudio
elementsource
element (2) (3) (4) (5)spacer
span
style
attributecite
elementmark
elementspan
element (2) (3)span
colgroup
element contains no col
elements, then the element may have a ... content attribute specified, whose value must be a valid non-negative integer greater than zero.colgroup
element (2) (3) (4)span
colgroup
element (2)span
col
element (2) (3)span
col
element (2)src
type
attribute, if the attribute is present, or of the type "text/javascript
", if the attribute is absent. A resource is a script resource of a given type if that type identifies a scripting language and the resource conforms with the requirements of that language's specification.script
element (2) (3) (4) (5) (6) (7) (8) (9)src
type
, charset
, and defer
, each must reflect the respective content attributes of the same name.script
element (2)src
alt
attribute provides equivalent content for those who cannot process images or who have image loading disabled.img
element (2) (3)src
alt
, ..., useMap
, and isMap
each must reflect the respective content attributes of the same name.img
element (2)src
iframe
element (2) (3) (4) (5)src
srcdoc
, name
, sandbox
, and seamless
must reflect the respective content attributes of the same name.iframe
element (2)src
embed
element (2) (3) (4)src
type
each must reflect the respective content attributes of the same name.embed
element (2)src
source
element (2)src
type
, and media
must reflect the respective content attributes of the same name.source
element (2)src
track
element (2)src
srclang
, label
, and default
IDL attributes must reflect the respective content attributes of the same name. The kind
IDL attribute must reflect the content attribute of the same name, limited to only known values.track
element (2)src
video
element (2) (3) (4)audio
element (2) (3) (4) (5)source
elementsrc
src
accept
, alt
, max
, min
, multiple
, pattern
, placeholder
, required
, size
, ..., and step
IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)src
src
attribute must be present, and must contain a valid non-empty URL potentially surrounded by spaces referencing a non-interactive, optionally animated, image resource that is neither paged nor scripted.input
element (2) (3)src
name
, scrolling
, and ... IDL attributes of the frame
element must reflect the respective content attributes of the same name.srcdoc
iframe
srcdoc
document.iframe
element (2) (3) (4) (5) (6) (7)srcdoc
src
, ..., name
, sandbox
, and seamless
must reflect the respective content attributes of the same name.iframe
element (2)srclang
kind
attribute is in the subtitles state. [BCP47]track
element (2) (3)srclang
src
, ..., label
, and default
IDL attributes must reflect the respective content attributes of the same name. The kind
IDL attribute must reflect the content attribute of the same name, limited to only known values.track
element (2)stalled
standby
object
elementsstandby
align
, archive
, border
, code
, declare
, hspace
, ..., and vspace
IDL attributes of the object
element must reflect the respective content attributes of the same name.start
ol
element (2)start
reversed
, ..., and type
IDL attributes must reflect the respective content attributes of the same name. The start
IDL attribute has the same default as its content attribute.ol
element (2) (3)startOffsetTime
History
interfacestep
accept
, alt
, max
, min
, multiple
, pattern
, placeholder
, required
, size
, src
, and ... IDL attributes must reflect the respective content attributes of the same name. The dirName
IDL attribute must reflect the dirname
content attribute. The readOnly
IDL attribute must reflect the readonly
content attribute. The defaultChecked
IDL attribute must reflect the checked
content attribute. The defaultValue
IDL attribute must reflect the value
content attribute.input
element (2)step
input
element (2) (3)step
attribute (2) (3)input
element APIs (2)strike
strong
em
elementstrong
element (2) (3) (4) (5)small
element (2)b
element (2)mark
elementstyle
style
attribute (2) (3) (4) (5) (6)style
dir
attributemeta
elementstyle
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)noscript
element (2) (3)stylesheet
link
elementalternate
" (2)stylesheet
" (2) (3)link
elementstyle
element (2)stylesheet
"sub
sub
and sup
elements (2) (3) (4) (5) (6) (7) (8) (9)submit
input
elementobject
elementinput
element (2)button
elementselect
elementtextarea
elementkeygen
elementsubscript
subtitles
track
elementtrack
element (2) (3) (4)subtitles
summary
details
element (2)summary
element (2) (3)summary
table
elementssummary
align
, frame
, ..., rules
, and width
, IDL attributes of the table
element must reflect the respective content attributes of the same name.sup
sub
and sup
elements (2) (3) (4) (5) (6) (7) (8) (9)superscript
suspend
svg
SYNTAX_ERR
innerHTML
(2)outerHTML
insertAdjacentHTML()
contenteditable
attributetabindex
tabindex
attribute (2) (3) (4)tabIndex
...
content attribute. Its default value is 0 for elements that are focusable and −1 for elements that are not focusable.tabindex
attributetable
table
element (2) (3) (4)caption
element (2) (3) (4) (5)colgroup
element (2) (3)col
elementtbody
element (2) (3) (4)thead
element (2) (3) (4)tfoot
element (2) (3) (4) (5) (6)tr
element (2)target
Document
cause navigation.base
element (2) (3) (4)iframe
elementtarget
base
element (2)target
href
, ..., rel
, media
, hreflang
, and type
, must reflect the respective content attributes of the same name.a
element (2)target
alt
, coords
, href
, ..., rel
, media
, hreflang
, and type
, each must reflect the respective content attributes of the same name.area
element (2)target
formtarget
content attributes, if specified, must have values that are valid browsing context names or keywords.form
element (2)formtarget
attribute, if the element is a submit button and has such an attribute; or the value of its form owner's ...
attribute, if it has such an attribute; or, if the Document
contains a base
element with a ...
attribute, then the value of the ...
attribute of the first such base
element; or, if there is no such element, the empty string.target
action
IDL attribute must reflect the content attribute of the same name, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The ... IDL attribute must reflect the content attribute of the same name. The method
and enctype
IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The encoding
IDL attribute must reflect the enctype
content attribute, limited to only known values. The noValidate
IDL attribute must reflect the novalidate
content attribute. The formAction
IDL attribute must reflect the formaction
content attribute, except that on getting, when the content attribute is missing or its value is the empty string, the document's address must be returned instead. The formEnctype
IDL attribute must reflect the formenctype
content attribute, limited to only known values. The formMethod
IDL attribute must reflect the formmethod
content attribute, limited to only known values. The formNoValidate
IDL attribute must reflect the formnovalidate
content attribute. The formTarget
IDL attribute must reflect the formtarget
content attribute.form
elementtarget
a
element (2)area
element (2)a
and area
elementstarget
link
elementstarget
charset
, rev
, and ... IDL attributes of the link
element must reflect the respective content attributes of the same name.tbody
table
element (2) (3) (4)colgroup
elementtbody
element (2) (3)thead
element (2)tfoot
element (2) (3)tr
element (2)td
thead
elementtr
element (2) (3) (4) (5)td
element (2)td
and th
elements (2) (3) (4) (5) (6) (7) (8)input
element (2)title
elementoption
elementtextarea
elementinput
element (2) (3) (4) (5)text
body
elementstext
body
element must reflect the element's ...
content attribute.dir
attributetitle
elementscript
elementnoscript
elementdfn
elementtrack
element (2)text/cache-manifest
text/cache-manifest
(2)text/html
iframe
element (2)text/html
(2) (3)text/html-sandboxed
(2) (3) (4) (5) (6) (7) (8)text/html-sandboxed
iframe
element (2) (3)text/html-sandboxed
(2) (3) (4) (5) (6) (7) (8) (9) (10) (11)textarea
dir
attributetextarea
element (2) (3) (4) (5) (6) (7) (8)track
element (2)tfoot
table
element (2) (3) (4) (5) (6) (7) (8)colgroup
elementtbody
elementthead
elementtfoot
element (2) (3) (4) (5)tr
elementth
thead
elementtr
element (2) (3)th
element (2) (3) (4) (5)td
and th
elements (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)Location
interfacebody
elementfooter
elementaddress
elementdir
attribute (2) (3) (4) (5) (6) (7) (8) (9) (10)textarea
elementDataTransferItem
interface (2) (3)dropzone
attribute (2)DataTransferItem
interfacedropzone
attribute (2)head
elementhtml
elementdir
attribute (2) (3) (4)noscript
elementpre
elementiframe
element (2)text/html
text/html-sandboxed
stylesheet
"title
elementthead
table
element (2) (3) (4) (5) (6)colgroup
elementtbody
element (2)thead
element (2) (3) (4) (5) (6)tfoot
element (2)tr
element (2)this
this
.time
article
elementtime
element (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)input
element (2)TIMEOUT_ERR
timeupdate
timeupdate
title
title
attribute (2) (3) (4) (5) (6) (7) (8)link
elementstyle
element (2)div
elementdfn
elementabbr
element (2) (3) (4) (5)img
elementpattern
attribute (2)placeholder
attributetextarea
elementmeter
element (2)stylesheet
"title
...
content attribute.title
attributetitle
head
element (2) (3)title
element (2) (3) (4)meta
elementpattern
attribute (2)History
interface (2)title
title
attribute defines alternative style sheet sets.link
element (2) (3) (4) (5)style
elementtitle
style
elements defines alternative style sheet sets. If the style
element has no title
attribute, then it has no title; the ...
attribute of ancestors does not apply to the style
element. [CSSOM]style
element (2) (3) (4)title
dfn
element has a ... attribute, then the exact value of that attribute is the term being defined. Otherwise, if it contains exactly one element child node and no child text nodes, and that child element is an abbr
element with a title
attribute, then the exact value of that attribute is the term being defined. Otherwise, it is the exact textContent
of the dfn
element that gives the term being defined.dfn
element (2) (3)title
abbr
element represents an abbreviation or acronym, optionally with its expansion. The ... attribute may be used to provide an expansion of the abbreviation. The attribute, if specified, must contain an expansion of the abbreviation, and nothing else.dfn
elementabbr
element (2)menu
element (2) (3)iframe
elementHistory
interfacetr
table
element (2) (3) (4) (5)colgroup
elementtbody
element (2) (3) (4) (5) (6)thead
element (2)tfoot
element (2) (3)tr
element (2)td
elementth
elementtrack
video
element (2)audio
element (2)source
elementtrack
element (2) (3) (4) (5)TrackList
objects (2) (3) (4) (5)translation
TrackList
objectsnoscript
element (2)a
elementins
elementdel
elementobject
elementvideo
element (2)audio
element (2)canvas
elementmap
elementdir
attributeol
elementselect
element (2)trueSpeed
type
link
element (2) (3)type
href
, rel
, media
, hreflang
, and ..., and sizes
each must reflect the respective content attributes of the same name.link
element (2)type
charset
parameter must not be specified. The default value for the type
attribute, which is used if the attribute is absent, is "text/css
". [RFC2318]style
element (2) (3) (4)type
media
, ... and scoped
IDL attributes must reflect the respective content attributes of the same name.style
element (2)type
charset
parameter must not be specified. The default, which is used if the attribute is absent, is "text/javascript
".script
element (2) (3) (4) (5) (6) (7)type
src
, ..., charset
, and defer
, each must reflect the respective content attributes of the same name.script
element (2)type
ol
element (2)type
reversed
, start
, and ... IDL attributes must reflect the respective content attributes of the same name. The start
IDL attribute has the same default as its content attribute.ol
element (2)type
href
, target
, rel
, media
, hreflang
, and ..., must reflect the respective content attributes of the same name.a
element (2)type
type
attribute and the src
attribute are present, then the type
attribute must specify the same type as the explicit Content-Type metadata of the resource given by the src
attribute.embed
element (2) (3) (4)type
src
and ... each must reflect the respective content attributes of the same name.embed
element (2)type
object
element (2) (3)type
data
, ..., name
, and useMap
each must reflect the respective content attributes of the same name.object
element (2)type
codecs
parameter, which certain MIME types define, might be necessary to specify exactly how the resource is encoded. [RFC4281]source
element (2) (3)type
src
, ..., and media
must reflect the respective content attributes of the same name.source
element (2)type
alt
, coords
, href
, target
, rel
, media
, hreflang
, and ..., each must reflect the respective content attributes of the same name.area
element (2)type
input
element (2) (3) (4) (5) (6)type
attributetype
autocomplete
and ... IDL attributes must reflect the respective content attributes of the same name, limited to only known values. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to
only non-negative numbers.input
element (2)type
command
element (2)type
a
element (2)area
element (2)a
and area
elementsalternate
" (2) (3) (4)type
param
elementstype
li
elementstype
ul
elementstype
li
element must reflect the content attribute of the same name.type
param
element must reflect the content attribute of the same name.type
compact
and ... IDL attributes of the ul
element must reflect the respective content attributes of the same name.TYPE_MISMATCH_ERR
u
u
element (2) (3) (4)mark
elementul
ol
element (2)ul
element (2) (3) (4)li
element (2)UNCACHED
undo
id
attribute (2)td
and th
elements (2) (3)form
element (2) (3)label
elementlist
attributeselect
element (2)output
elementunlink
iframe
elementtd
and th
elementsoutput
elementicon
"dropzone
attributeunselect
updateready
UPDATEREADY
ol
elementol
elementbase
elementiframe
elementa
element (2) (3)area
element (2) (3)Location
interface (2)URL_MISMATCH_ERR
urn
a
elementsurn
link
elementsuseMap
alt
, src
, ..., and isMap
each must reflect the respective content attributes of the same name.img
element (2)useMap
data
, type
, name
, and ... each must reflect the respective content attributes of the same name.object
element (2)usemap
img
element or an object
element representing an image, may be associated with an image map (in the form of a map
element) by specifying a ... attribute on the img
or object
element. The usemap
attribute, if specified, must be a valid hash-name reference to a map
element.img
element (2) (3)object
element (2) (3)usemap
input
elementsuseMap
input
element must reflect the element's ...
content attribute.iframe
elementobject
elementbase
elementa
and area
elementstime
elementtime
elementtime
elementtime
elementins
and del
elementsstep
attributeprogress
elementmeter
elementol
elementli
elementtabindex
attributearea
elementlink
elementstyle
elementsource
elementa
and area
elementslink
elementstyle
elementscript
elementembed
elementobject
elementsource
elementa
and area
elementshtml
elementlink
elementscript
elementimg
elementiframe
elementembed
elementobject
elementvideo
elementsource
elementtrack
elementcommand
elementcanvas
elementcolgroup
elementcol
elementtd
and th
elements (2)size
attributeselect
elementtextarea
element (2)icon
"base
elementblockquote
elementq
elementins
and del
elementsa
and area
elementsVALIDATION_ERR
validity
object
elementfieldset
elementinput
elementbutton
elementselect
elementtextarea
elementkeygen
elementoutput
elementvalign
col
elementsvalign
tbody
, thead
, and tfoot
elementsvalign
td
and th
elementsvalign
tr
elementsvAlign
col
element must reflect the element's ...
content attribute.vAlign
tbody
, thead
, and tfoot
element must reflect the elements' ...
content attributes.vAlign
td
and th
element must reflect the elements' ...
content attributes.vAlign
tr
element must reflect the element's ...
content attribute.value
li
element (2)value
value
content attribute.li
element (2) (3)value
name
and ... must both reflect the respective content attributes of the same name.param
element (2)value
input
element.input
element (2) (3)maxlength
attributevalue
option
element is the value of the value
attribute, if there is one, or the textContent
of the element, if there isn't.list
attributeoption
element (2) (3) (4)option
element is the value of the ...
attribute, if there is one, or the textContent
of the element, if there isn't.select
elementdatalist
element (2)option
elementvalue
max
attribute specifies how much work the task requires in total. The units are arbitrary and not specified.progress
element (2) (3) (4) (5) (6)value
value
content attribute must be set to that string.progress
element (2) (3)value
min
attribute specifies the lower bound of the range, and the max
attribute specifies the upper bound. The ... attribute specifies the value to have the gauge indicate as the "measured" value.meter
element (2) (3) (4) (5)value
value
content attribute must be set to that string.meter
element (2) (3)valuetype
param
elementsvalueType
param
element must reflect the element's ...
content attribute.var
var
element (2) (3) (4)sub
and sup
elementsversion
html
elementsversion
html
element must reflect the content attribute of the same name.video
object
element (2) (3)video
element (2) (3) (4) (5) (6)source
elementvlink
body
elementsvLink
body
element must reflect the element's ...
content attribute.volumechange
volumechange
vspace
embed
elementsembed
elementvspace
iframe
elementsvspace
input
elementsvspace
img
elementsvspace
object
elementsvspace
align
, alt
, archive
, code
, height
, hspace
, name
, object
, ..., and width
IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.vspace
behavior
, direction
, height
, hspace
, ..., and width
IDL attributes must reflect the respective content attributes of the same name.vspace
name
, align
, border
, hspace
, and ... IDL attributes of the img
element must reflect the respective content attributes of the same name.vspace
align
, archive
, border
, code
, declare
, hspace
, standby
, and ... IDL attributes of the object
element must reflect the respective content attributes of the same name.waiting
waiting
wbr
wbr
element (2) (3)width
canvas
element has two attributes to control the size of the coordinate space: ... and height
. These attributes, when specified, must have values that are valid non-negative integers. The width
attribute defaults to 300, and the height
attribute defaults to 150.canvas
element (2) (3)width
height
IDL attributes must reflect the respective content attributes of the same name, with the same defaults.canvas
element (2)width
height
attributes on img
, iframe
, embed
, object
, video
, and, when their type
attribute is in the Image Button state, input
elements may be specified to give the dimensions of the visual content of the element (the width and height respectively, relative to the nominal direction of the output medium), in CSS pixels. The attributes, if specified, must have values that are valid non-negative
integers.img
element (2) (3)iframe
elementembed
elementobject
elementvideo
elementinput
element (2) (3)width
height
IDL attributes on the iframe
, embed
, object
, and video
elements must reflect the respective content attributes of the same name.iframe
elementembed
elementobject
elementvideo
elementinput
elementwidth
col
elementswidth
hr
elementswidth
pre
elementswidth
table
elementswidth
td
and th
elementswidth
align
, alt
, archive
, code
, height
, hspace
, name
, object
, vspace
, and ... IDL attributes must reflect the respective content attributes of the same name. For the purposes of reflection, the applet
element's object
content attribute is defined as containing a URL.width
behavior
, direction
, height
, hspace
, vspace
, and ... IDL attributes must reflect the respective content attributes of the same name.width
align
and ... IDL attributes of the col
element must reflect the respective content attributes of the same name.width
align
, color
, size
, and ... IDL attributes of the hr
element must reflect the respective content attributes of the same name.width
pre
element must reflect the content attribute of the same name.width
align
, frame
, summary
, rules
, and ..., IDL attributes of the table
element must reflect the respective content attributes of the same name.width
abbr
, align
, axis
, height
, and ... IDL attributes of the td
and th
elements must reflect the respective content attributes of the same name.body
element (2) (3) (4) (5)img
elementiframe
elementWindow
object (2) (3) (4)Window
objectwrap
soft
keyword which maps to the Soft state, and the hard
keyword which maps to the Hard state. The missing value default is the Soft state.textarea
element (2) (3)wrap
cols
, placeholder
, required
, rows
, and ... attributes must reflect the respective content attributes of the same name. The cols
and rows
attributes are limited to only non-negative numbers greater than zero. The
cols
attribute's default value is 20. The rows
attribute's default value is 2. The dirName
IDL attribute must reflect the dirname
content attribute. The maxLength
IDL attribute must reflect the maxlength
content attribute, limited to only non-negative
numbers. The readOnly
IDL attribute must reflect the readonly
content attribute.textarea
element (2)WRONG_DOCUMENT_ERR
lang
and xml:lang
attributesxml:base
attribute (XML only)document.write()
document.writeln()
innerHTML
(2)outerHTML
insertAdjacentHTML()
meta
elementnoscript
elementiframe
element (2)application/xhtml+xml
lang
and xml:lang
attributesdata-*
attributesembed
elementAll references are normative unless marked "Non-normative".
XMLHttpRequest
, A. van Kesteren. W3C.Thanks to Tim Berners-Lee for inventing HTML, without which none of this would exist.
Thanks to Aankhen, Aaron Boodman, Aaron Leventhal, Adam Barth, Adam de Boor, Adam Hepton, Adam Roben, Addison Phillips, Adele Peterson, Adrian Bateman, Adrian Sutton, Agustín Fernández, Ajai Tirumali, Akatsuki Kitamura, Alan Plum, Alastair Campbell, Alejandro G. Castro, Alex Bishop, Alex Nicolaou, Alex Rousskov, Alexander J. Vincent, Alexey Feldgendler, Алексей Проскуряков (Alexey Proskuryakov), Alexis Deveria, Allan Clements, Amos Jeffries, Anders Carlsson, Andreas, Andreas Kling, Andrei Popescu, André E. Veltstra, Andrew Barfield, Andrew Clover, Andrew Gove, Andrew Grieve, Andrew Oakley, Andrew Sidwell, Andrew Smith, Andrew W. Hagen, Andrey V. Lukyanov, Andy Heydon, Andy Palay, Anne van Kesteren, Anthony Boyd, Anthony Bryan, Anthony Hickson, Anthony Ricaud, Antti Koivisto, Arne Thomassen, Aron Spohr, Arphen Lin, Aryeh Gregor, Asbjørn Ulsberg, Ashley Sheridan, Atsushi Takayama, Aurelien Levy, Ave Wrigley, Ben Boyle, Ben Godfrey, Ben Lerner, Ben Leslie, Ben Meadowcroft, Ben Millard, Benjamin Carl Wiley Sittler, Benjamin Hawkes-Lewis, Bert Bos, Bijan Parsia, Bil Corry, Bill Mason, Bill McCoy, Billy Wong, Bjartur Thorlacius, Björn Höhrmann, Blake Frantz, Boris Zbarsky, Brad Fults, Brad Neuberg, Brad Spencer, Brady Eidson, Brendan Eich, Brenton Simpson, Brett Wilson, Brett Zamir, Brian Campbell, Brian Korver, Brian Kuhn, Brian Ryner, Brian Smith, Brian Wilson, Bryan Sullivan, Bruce D'Arcus, Bruce Lawson, Bruce Miller, C. Williams, Cameron McCormack, Cao Yipeng, Carlos Gabriel Cardona, Carlos Perelló Marín, Chao Cai, 윤석찬 (Channy Yun), Charl van Niekerk, Charles Iliya Krempeaux, Charles McCathieNevile, Chris Apers, Chris Cressman, Chris Evans, Chris Morris, Chris Pearce, Christian Biesinger, Christian Johansen, Christian Schmidt, Christopher Aillon, Chriswa, Clark Buehler, Cole Robison, Colin Fine, Collin Jackson, Corprew Reed, Craig Cockburn, Csaba Gabor, Csaba Marton, Cynthia Shelly, Dan Yoder, Daniel Barclay, Daniel Bratell, Daniel Brooks, Daniel Brumbaugh Keeney, Daniel Cheng, Daniel Davis, Daniel Glazman, Daniel Peng, Daniel Schattenkirchner, Daniel Spång, Daniel Steinberg, Danny Sullivan, Darin Adler, Darin Fisher, Darxus, Dave Camp, Dave Hodder, Dave Lampton, Dave Singer, Dave Townsend, David Baron, David Bloom, David Bruant, David Carlisle, David E. Cleary, David Egan Evans, David Flanagan, David Gerard, David Håsäther, David Hyatt, David I. Lehn, David John Burrowes, David Matja, David Remahl, David Smith, David Woolley, DeWitt Clinton, Dean Edridge, Dean Edwards, Debi Orton, Derek Featherstone, Devdatta, Dimitri Glazkov, Dimitry Golubovsky, Dirk Pranke, Divya Manian, Dmitry Titov, dolphinling, Dominique Hazaël-Massieux, Don Brutzman, Doron Rosenberg, Doug Kramer, Doug Simpkinson, Drew Wilson, Edmund Lai, Eduard Pascual, Eduardo Vela, Edward O'Connor, Edward Welbourne, Edward Z. Yang, Eira Monstad, Eitan Adler, Eliot Graff, Elizabeth Castro, Elliott Sprehn, Elliotte Harold, Eric Carlson, Eric Law, Eric Rescorla, Eric Semling, Erik Arvidsson, Erik Rose, Evan Martin, Evan Prodromou, Evert, fantasai, Felix Sasaki, Francesco Schwarz, Francis Brosnan Blazquez, Franck 'Shift' Quélain, Frank Barchard, 鵜飼文敏 (Fumitoshi Ukai), Futomi Hatano, Gavin Carothers, Gareth Rees, Garrett Smith, Geoffrey Garen, Sam Sneddon, George Lund, Gianmarco Armellin, Giovanni Campagna, Glenn Adams, Glenn Maynard, Graham Klyne, Greg Botten, Greg Houston, Greg Wilkins, Gregg Tavares, Gregory J. Rosmaita, Grey, Guilherme Johansson Tramontina, Gytis Jakutonis, Håkon Wium Lie, Hallvord Reiar Michaelsen Steen, Hans S. Tømmerhalt, Hans Stimer, Harald Alvestrand, Henri Sivonen, Henrik Lied, Henry Mason, Hugh Winkler, Ian Bicking, Ian Davis, Ignacio Javier, Ivan Enderlin, Ivo Emanuel Gonçalves, J. King, Jacques Distler, James Craig, James Graham, James Justin Harrell, James M Snell, James Perrett, James Robinson, Jamie Lokier, Jan-Klaas Kollhof, Jason Kersey, Jason Lustig, Jason White, Jasper Bryant-Greene, Jatinder Mann, Jed Hartman, Jeff Balogh, Jeff Cutsinger, Jeff Schiller, Jeff Walden, Jeffrey Zeldman, 胡慧鋒 (Jennifer Braithwaite), Jens Bannmann, Jens Fendler, Jens Lindström, Jens Meiert, Jeremy Keith, Jeremy Orlow, Jeroen van der Meer, Jian Li, Jim Jewett, Jim Ley, Jim Meehan, Jjgod Jiang, João Eiras, Joe Clark, Joe Gregorio, Joel Spolsky, Johan Herland, John Boyer, John Bussjaeger, John Carpenter, John Fallows, John Foliot, John Harding, John Keiser, John Snyders, John-Mark Bell, Johnny Stenback, Jon Ferraiolo, Jon Gibbins, Jon Perlow, Jonas Sicking, Jonathan Cook, Jonathan Rees, Jonathan Worent, Jonny Axelsson, Jorgen Horstink, Jorunn Danielsen Newth, Joseph Kesselman, Joseph Pecoraro, Josh Aas, Josh Levenberg, Joshua Bell, Joshua Randall, Jukka K. Korpela, Jules Clément-Ripoche, Julian Reschke, Jürgen Jeka, Justin Lebar, Justin Schuh, Justin Sinclair, Kai Hendry, Kartikaya Gupta, Kathy Walton, Kelly Norton, Kevin Benson, Kornél Pál, Kornel Lesinski, Kris Northfield, Kristof Zelechovski, Krzysztof Maczyński, 黒澤剛志 (Kurosawa Takeshi), Kyle Hofmann, Kyle Huey, Léonard Bouchet, Lachlan Hunt, Larry Masinter, Larry Page, Lars Gunther, Lars Solberg, Laura Carlson, Laura Granka, Laura L. Carlson, Laura Wisewell, Laurens Holst, Lee Kowalkowski, Leif Halvard Silli, Lenny Domnitser, Leons Petrazickis, Lobotom Dysmon, Logan, Loune, Luke Kenneth Casson Leighton, Maciej Stachowiak, Magnus Kristiansen, Maik Merten, Malcolm Rowe, Mark Birbeck, Mark Miller, Mark Nottingham, Mark Pilgrim, Mark Rowe, Mark Schenk, Mark Wilton-Jones, Martijn Wargers, Martin Atkins, Martin Dürst, Martin Honnen, Martin Janecke, Martin Kutschker, Martin Nilsson, Martin Thomson, Masataka Yakura, Mathieu Henri, Matias Larsson, Matt Schmidt, Matt Wright, Matthew Gregan, Matthew Mastracci, Matthew Raymond, Matthew Thomas, Mattias Waldau, Max Romantschuk, Menno van Slooten, Micah Dubinko, Michael 'Ratt' Iannarelli, Michael A. Nachbaur, Michael A. Puls II, Michael Carter, Michael Daskalov, Michael Enright, Michael Gratton, Michael Nordman, Michael Powers, Michael Rakowski, Michael(tm) Smith, Michal Zalewski, Michel Fortin, Michelangelo De Simone, Michiel van der Blonk, Mihai Şucan, Mihai Parparita, Mike Brown, Mike Dierken, Mike Dixon, Mike Schinkel, Mike Shaver, Mikko Rantalainen, Mohamed Zergaoui, Mounir Lamouri, Ms2ger, NARUSE Yui, Neil Deakin, Neil Rashbrook, Neil Soiffer, Nicholas Shanks, Nicholas Stimpson, Nicholas Zakas, Nickolay Ponomarev, Nicolas Gallagher, Noah Mendelsohn, Noah Slater, NoozNooz42, Ojan Vafai, Olaf Hoffmann, Olav Junker Kjær, Oldřich Vetešník, Oli Studholme, Oliver Hunt, Oliver Rigby, Olivier Gendrin, Olli Pettay, oSand, Patrick H. Lauke, Patrik Persson, Paul Norman, Per-Erik Brodin, Perry Smith, Peter Beverloo, Peter Karlsson, Peter Kasting, Peter Stark, Peter-Paul Koch, Phil Pickering, Philip Jägenstedt, Philip Taylor, Philip TAYLOR, Prateek Rungta, Pravir Gupta, Rachid Finge, Rajas Moonka, Ralf Stoltze, Ralph Giles, Raphael Champeimont, Remco, Remy Sharp, Rene Saarsoo, Rene Stach, Ric Hardacre, Rich Doughty, Richard Ishida, Rigo Wenning, Rikkert Koppes, Rimantas Liubertas, Riona Macnamara, Rob Ennals, Rob Jellinghaus, Robert Blaut, Robert Collins, Robert O'Callahan, Robert Sayre, Robin Berjon, Rodger Combs, Roland Steiner, Roman Ivanov, Roy Fielding, Ruud Steltenpool, Ryan King, Ryosuke Niwa, S. Mike Dierken, Salvatore Loreto, Sam Dutton, Sam Kuper, Sam Ruby, Sam Weinig, Sander van Lambalgen, Sarven Capadisli, Scott González, Scott Hess, Sean Fraser, Sean Hayes, Sean Hogan, Sean Knapp, Sebastian Markbåge, Sebastian Schnitzenbaumer, Seth Call, Shanti Rao, Shaun Inman, Shiki Okasaka, Sierk Bornemann, Sigbjørn Vik, Silvia Pfeiffer, Simon Montagu, Simon Pieters, Simon Spiegel, skeww, Stanton McCandlish, Stefan Håkansson, Stefan Haustein, Stefan Santesson, Stefan Weiss, Steffen Meschkat, Stephen Ma, Steve Faulkner, Steve Runyon, Steven Bennett, Steven Garrity, Steven Tate, Stewart Brodie, Stuart Ballard, Stuart Parmenter, Subramanian Peruvemba, Sunava Dutta, Susan Borgrink, Susan Lesch, Sylvain Pasche, T. J. Crowder, Tab Atkins, Tantek Çelik, 田村健人 (TAMURA Kent), Ted Mielczarek, Terrence Wood, Thomas Broyer, Thomas Koetter, Thomas O'Connor, Tim Altman, Tim Johansson, Toby Inkster, Todd Moody, Tom Baker, Tom Pike, Tommy Thorsen, Travis Leithead, Tyler Close, Vladimir Katardjiev, Vladimir Vukićević, voracity, Wakaba, Wayne Carr, Wayne Pollock, Wellington Fernando de Macedo, Weston Ruter, Will Levine, William Swanson, Wladimir Palant, Wojciech Mach, Wolfram Kriesing, Yang Chen, Ye-Kui Wang, Yehuda Katz, Yi-An Huang, Yngve Nysaeter Pettersen, Yuzo Fujishima, Zhenbin Xu, Zoltan Herczeg, and Øistein E. Andersen, for their useful comments, both large and small, that have led to changes to this specification over the years.
Thanks also to everyone who has ever posted about HTML to their blogs, public mailing lists, or forums, including all the contributors to the various W3C HTML WG lists and the various WHATWG lists.
Special thanks to Richard Williamson for creating the first implementation of canvas
in Safari, from which the canvas feature was designed.
Special thanks also to the Microsoft employees who first implemented the event-based drag-and-drop mechanism, contenteditable
, and other features first widely deployed by the Windows Internet Explorer browser.
Thanks to the SubRip community, including in particular Zuggy and ai4spam, for their work on the SubRip software program whose SRT file format was used as the basis for the WebVTT text track file format.
Thanks to the many sources that provided inspiration for the examples used in the specification.
Thanks also to the Microsoft blogging community for some ideas, to the attendees of the W3C Workshop on Web Applications and Compound Documents for inspiration, to the #mrt crew, the #mrt.no crew, and the #whatwg crew, and to Pillar and Hedral for their ideas and support.