HTML 5.2: 11. Obsolete features

11. Obsolete features

11.1. Obsolete but conforming features

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 tree 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 tree. 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 fragments in URLs. The id attribute should be used instead.

Authors should not, but may despite requirements to the contrary elsewhere in this specification, specify the maxlength and size attributes on input elements whose type attributes are in the Number state. One valid reason for using these attributes regardless is to help legacy user agents that do not support input elements with type="number" to still render the text control with a useful width.

11.1.1. Warnings for obsolete but conforming features

To ease the transition from HTML Transitional documents to the language defined in this specification, and to discourage certain features that are only allowed in very few circumstances, conformance checkers must warn the user when the following features are used in a document. These are generally old obsolete features that have no effect, and are allowed only to distinguish between likely mistakes (regular conformance errors) and mere vestigial markup or unusual and discouraged practices (these warnings).

The following features must be categorized as described above:

The presence of a border attribute on an img element if its value is the string "0".
The presence of a language attribute on a script element if its value is an ASCII case-insensitive match for the string "JavaScript" and if there is no type attribute or there is and its value is an ASCII case-insensitive match for the string "text/javascript".
The presence of a name attribute on an a element, if its value is not the empty string.
The presence of a maxlength attribute on an input element whose type attribute is in the Number state.
The presence of a size attribute on an input element whose type attribute is in the Number state.

Conformance checkers must distinguish between pages that have no conformance errors and have none of these obsolete features, and pages that have no conformance errors but do have some of these obsolete features.

For example, a validator could report some pages as "Valid HTML" and others as "Valid HTML with warnings".

11.2. Non-conforming features

Elements in the following list are entirely obsolete, and must not be used by authors:

applet

Use embed or object instead.

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 control combination instead.

listing

Use pre and code instead.

nextid

Use GUIDs instead.

noembed

Use object instead of embed when fallback is necessary.

plaintext

Use the "text/plain" MIME type instead.

rb

rtc

Providing the ruby base directly inside the ruby element or using nested ruby elements is sufficient.

strike

Use del instead if the element is marking an edit, otherwise use s instead.

xmp

Use pre and code instead, and escape "<" and "&" characters as "<" and "&" respectively.

basefont

big

blink

center

font

marquee

menu

menuitem

multicol

nobr

spacer

tt

Use appropriate elements 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 elements
charset on link elements: Use an HTTP Content-Type header on the linked resource instead.
coords on a elements
shape on a elements: Use area instead of a for image maps.
methods on a elements
methods on link elements: Use the HTTP OPTIONS feature instead.
name on a elements (except as noted in the previous section)
name on embed elements
name on img elements
name on option elements: Use the id attribute instead.
urn on a elements
urn on link elements: Specify the preferred persistent identifier using the href attribute instead.
accept on form elements: Use the accept attribute directly on the input elements instead.
hreflang on area elements
type on area elements: These attributes do not do anything useful, and for historical reasons there are no corresponding IDL attributes on area elements. Omit them altogether.
nohref on area elements: Omitting the href attribute is sufficient; the nohref attribute is unnecessary. Omit it altogether.
profile on head elements: When 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 elements: Unnecessary. Omit it altogether.
ismap on input elements: Unnecessary. Omit it altogether. All input elements with a type attribute in the Image Button state are processed as server-side image maps.
usemap on input elements: Use img instead of input for image maps.
longdesc on iframe elements
longdesc on img elements: Use 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 elements: Use a progressive JPEG image (given in the src attribute), instead of using two separate images.
target on link elements: Unnecessary. Omit it altogether.
scheme on meta elements: If more than one scheme needs to be declared for a meta element make the scheme declaration part of the value.
archive on object elements
classid on object elements
code on object elements
codebase on object elements
codetype on object elements: Use 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 elements: Repeat the object element completely each time the resource is to be reused.
standby on object elements: Optimize the linked resource so that it loads quickly or, at least, incrementally.
type on param elements
valuetype on param elements: Use 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 elements
for on script elements: Use DOM events mechanisms to register event listeners. [DOM41]
datapagesize on table elements: Unnecessary. Omit it altogether.
summary on table elements: Use one of the techniques given in the table section instead.
abbr on td elements: Use 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. If it’s a heading, use th (which has an abbr attribute).
axis on td and th elements: Use the scope attribute on the relevant th.
scope on td elements: Use th elements for heading cells.
datasrc on a, applet, button, div, frame, iframe, img, input, label, legend, marquee, object, option, select, a, table, and textarea elements
datafld on a, applet, button, div, fieldset, frame, iframe, img, input, label, legend, marquee, object, param, select, a, and textarea elements
dataformatas on button, div, input, label, legend, marquee, object, option, select, a, and table elements: Use script and a mechanism such as XMLHttpRequest to populate the page dynamically. [XHR]
alink on body elements
bgcolor on body elements
bottommargin on body elements
leftmargin on body elements
link on body elements
marginheight on body elements
marginwidth on body elements
rightmargin on body elements
text on body elements
topmargin on body elements
vlink on body elements
clear on br elements
align on caption elements
align on col elements
char on col elements
charoff on col elements
valign on col elements
width on col elements
align on div elements
compact on dl elements
align on embed elements
hspace on embed elements
vspace on embed elements
bordercolor on frame elements
align on hr elements
color on hr elements
noshade on hr elements
size on hr elements
width on hr elements
align on h1—h6 elements
align on iframe elements
allowtransparency on iframe elements
frameborder on iframe elements
framespacing on iframe elements
hspace on iframe elements
marginheight on iframe elements
marginwidth on iframe elements
scrolling on iframe elements
vspace on iframe elements
align on input elements
border on input elements
hspace on input elements
vspace on input elements
align on img elements
border on img elements (except as noted in the previous section)
hspace on img elements
vspace on img elements
align on legend elements
type on li elements
compact on menu elements
bgcolor on marquee elements
height on marquee elements
hspace on marquee elements
vspace on marquee elements
width on marquee elements
align on object elements
border on object elements
hspace on object elements
vspace on object elements
compact on ol elements
align on p elements
width on pre elements
align on table elements
bgcolor on table elements
border on table elements
bordercolor on table elements
cellpadding on table elements
cellspacing on table elements
frame on table elements
height on table elements
rules on table elements
width on table elements
align on tbody, thead, and tfoot elements
char on tbody, thead, and tfoot elements
charoff on tbody, thead, and tfoot elements
valign on tbody, thead, and tfoot elements
align on td and th elements
bgcolor on td and th elements
char on td and th elements
charoff on td and th elements
height on td and th elements
nowrap on td and th elements
valign on td and th elements
width on td and th elements
align on tr elements
bgcolor on tr elements
char on tr elements
charoff on tr elements
height on tr elements
valign on tr elements
compact on ul elements
type on ul elements
background on body, table, thead, tbody, tfoot, tr, td, and th elements: Use CSS instead.

11.3. Requirements for implementations

11.3.1. The `applet` element

This feature is in the process of being removed from the Web platform. (This is a long process that takes many years.) Using the applet element at this time is highly discouraged.

The applet element is a Java-specific variant of the embed element. The applet element is now obsoleted so that all extension frameworks (Java, .NET, Flash, etc) are handled in a consistent manner.

When the element matches any of the following conditions, it represents its contents:

The element is still in the stack of open elements of an HTML parser or XML parser.
The element is not in a document.
The element’s node document is not fully active.
The element’s node document's active sandboxing flag set has its sandboxed plugins browsing context flag set.
The element has an ancestor media element.
The element has an ancestor object element that is not showing its fallback content.
No Java Language runtime plugin is available.
A Java runtime plugin is available but it is disabled.
The Should element be blocked a priori by Content Security Policy? algorithm returns "Blocked" when executed on the element. [CSP3]

Otherwise, the user agent should instantiate a Java Language runtime plugin, and should pass the names and values of all the attributes on the element, in the order they were added to the element, with the attributes added by the parser being ordered in source order, and then a parameter named "PARAM" whose value is null, and then all the names and values of parameters given by param elements that are children of the applet element, in tree order, to the plugin used. If the plugin supports a scriptable interface, the HTMLAppletElement object representing the element should expose that interface. The applet element represents the plugin.

The applet element is unaffected by the CSS display property. The Java Language runtime is instantiated even if the element is hidden with a 'display:none' CSS style.

The applet element must implement the HTMLAppletElement interface.

// Note: intentionally not [HTMLConstructor]
interface HTMLAppletElement : HTMLElement {
  attribute DOMString align;
  attribute DOMString alt;
  attribute DOMString archive;
  attribute DOMString code;
  attribute USVString codeBase;
  attribute DOMString height;
  attribute unsigned long hspace;
  attribute DOMString name;
  attribute USVString _object; // the underscore is not part of the identifier
  attribute unsigned long vspace;
  attribute DOMString width;
};

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.

11.3.2. The `marquee` element

The marquee element is a presentational element that animates content. CSS transitions and animations are a more appropriate mechanism. [CSS3-ANIMATIONS] [CSS3-TRANSITIONS]

The task source for tasks mentioned in this section is the DOM manipulation task source.

The marquee element must implement the HTMLMarqueeElement interface.

[HTMLConstructor]
interface HTMLMarqueeElement : HTMLElement {
  [CEReactions] attribute DOMString behavior;
  [CEReactions] attribute DOMString bgColor;
  [CEReactions] attribute DOMString direction;
  [CEReactions] attribute DOMString height;
  [CEReactions] attribute unsigned long hspace;
  [CEReactions] attribute long loop;
  [CEReactions] attribute unsigned long scrollAmount;
  [CEReactions] attribute unsigned long scrollDelay;
  [CEReactions] attribute boolean trueSpeed;
  [CEReactions] attribute unsigned long vspace;
  [CEReactions] attribute DOMString width;

  attribute EventHandler onbounce;
  attribute EventHandler onfinish;
  attribute EventHandler onstart;

  void start();
  void stop();
};

A marquee element can be turned on or turned off. When it is created, it is turned on.

When the start() method is called, the marquee element must be turned on.

When the stop() method is called, the marquee element must be turned off.

When a marquee element is created, the user agent must queue a task to fire an event named start at the element.

The behavior content attribute on marquee elements is an enumerated attribute with the following keywords (all non-conforming):

Keyword	State
`scroll`	scroll
`slide`	slide
`alternate`	alternate

The missing value default is the scroll state.

The direction content attribute on marquee elements is an enumerated attribute with the following keywords (all non-conforming):

Keyword	State
`left`	left
`right`	right
`up`	up
`down`	down

The missing value default is the left state.

The truespeed content attribute on marquee elements is a boolean attribute.

A marquee element has a marquee scroll interval, which is obtained as follows:

If the element has a scrolldelay attribute, and parsing its value using the rules for parsing non-negative integers does not return an error, then let delay be the parsed value. Otherwise, let delay be
If the element does not have a truespeed attribute, and the delay value is less than 60, then let delay be 60 instead.
The marquee scroll interval is delay, interpreted in milliseconds.

A marquee element has a marquee scroll distance, which, if the element has a scrollamount attribute, and parsing its value using the rules for parsing non-negative integers does not return an error, is the parsed value interpreted in CSS pixels, and otherwise is 6 CSS pixels.

A marquee element has a marquee loop count, which, if the element has a loop content attribute, and parsing its value using the rules for parsing integers does not return an error or a number less than 1, is the parsed value, and otherwise is -1.

The loop IDL attribute, on getting, must return the element’s marquee loop count; and on setting, if the new value is different than the element’s marquee loop count and either greater than zero or equal to -1, must set the element’s loop content attribute (adding it if necessary) to the valid integer that represents the new value. (Other values are ignored.)

A marquee element also has a marquee current loop index, which is zero when the element is created.

The rendering layer will occasionally increment the marquee current loop index, which must cause the following steps to be run:

If the marquee loop count is -1, then abort these steps.
Increment the marquee current loop index by one.
If the marquee current loop index is now equal to or greater than the element’s marquee loop count, turn off the marquee element and queue a task to fire an event named finish at the marquee element.

Otherwise, if the behavior attribute is in the alternate state, then queue a task to fire an event named bounce at the marquee element.

Otherwise, queue a task to fire an event named start at the marquee element.

The following are the event handlers (and their corresponding event handler event types) that must be supported, as event handler content attributes and event handler IDL attributes, by marquee elements:

Event handler	Event handler event type
`onbounce`	`bounce`
`onfinish`	`finish`
`onstart`	`start`

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.

11.3.3. Frames

The frameset element acts as the body element in documents that use frames.

The frameset element must implement the HTMLFrameSetElement interface.

[HTMLConstructor]
interface HTMLFrameSetElement : HTMLElement {
  [CEReactions] attribute DOMString cols;
  [CEReactions] attribute DOMString rows;
};
HTMLFrameSetElement implements WindowEventHandlers;

The cols and rows content attributes for the frameset element.

The cols and rows IDL attributes of the frameset element must reflect the respective content attributes of the same name.

The frameset 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, onresize, and onscroll event handlers of the Window object, exposed on the frameset element, replace the generic event handlers with the same names normally supported by HTML elements.

The frame element defines a nested browsing context similar to the iframe element, but rendered within a frameset element.

A frame element is said to be an active frame element when it is in a document.

When a frame element is created as an active frame element, or becomes an active frame element after not having been one, the user agent must create a new browsing context, set the element’s nested browsing context to the newly-created browsing context, and then process the frame attributes for the first time. If the element has a name attribute, the browsing context name must be set to the value of this attribute; otherwise, the browsing context name must be set to the empty string.

When a frame element stops being an active frame element, the user agent must discard the element’s nested browsing context, and then set the element’s nested browsing context to null..

Whenever a frame element with a non-null nested browsing context has its src attribute set, changed, or removed, the user agent must process the frame attributes.

When the user agent is to process the frame attributes, it must run the first appropriate steps from the following list:

If the element has no src attribute specified, and the user agent is processing the frame's attributes for the first time: Queue a task to fire an event named load at the frame element.
Otherwise: Run the otherwise steps for iframe or frame elements.

Any navigation required of the user agent in the process the frame attributes algorithm must use the frame element’s node document's browsing context as the source browsing context.

Furthermore, if the active document of the element’s nested browsing context before such a navigation was not completely loaded at the time of the new navigation, then the navigation must be completed with replacement enabled.

Similarly, if the nested browsing context's session history contained only one Document when the process the frame attributes algorithm was invoked, and that was the about:blank Document created when the nested browsing context was created, then any navigation required of the user agent in that algorithm must be completed with replacement enabled.

When a Document in a frame is marked as completely loaded, the user agent must queue a task to fire an event named load at the frame element.

The task source for the tasks above is the DOM manipulation task source.

When a frame element’s has a non-null nested browsing context, and its nested browsing context's active document is not ready for post-load tasks, and when anything is delaying the load event of the frame element’s browsing context's active document, and when the frame element’s browsing context is in the delaying load events mode, the frame must delay the load event of its document.

Whenever the <name attribute is set and the frame element’s nested browsing context is non-null, the nested browsing context's name must be changed to the new value. If the attribute is removed, the browsing context name must be set to the empty string.

The frame element must implement the HTMLFrameElement interface.

[HTMLConstructor]
interface HTMLFrameElement : HTMLElement {
  [CEReactions] attribute DOMString name;
  [CEReactions] attribute DOMString scrolling;
  [CEReactions] attribute USVString src;
  [CEReactions] attribute DOMString frameBorder;
  [CEReactions] attribute USVString longDesc;
  [CEReactions] attribute boolean noResize;
  readonly attribute Document? contentDocument;
  readonly attribute WindowProxy? contentWindow;

  [CEReactions, TreatNullAs=EmptyString] attribute DOMString marginHeight;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString marginWidth;
};

The name, scrolling, and src IDL attributes of the frame element must reflect the respective content attributes of the same name. For the purposes of reflection, the frame element’s src content attribute is defined as containing a URL.

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 noResize IDL attribute of the frame element must reflect the element’s noresize content attribute.

The contentDocument IDL attribute, on getting, must return the content document.

The contentWindow IDL attribute must return the WindowProxy object of the frame element’s nested browsing context, if the element’s nested browsing context is non-null, or return null otherwise.

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.

11.3.4. Other elements, attributes and APIs

User agents must treat acronym elements in a manner equivalent to abbr elements in terms of semantics and for purposes of rendering.

partial interface HTMLAnchorElement {
  [CEReactions] attribute DOMString coords;
  [CEReactions] attribute DOMString charset;
  [CEReactions] attribute DOMString name;
  [CEReactions] attribute DOMString shape;
};

The coords, charset, name, and shape IDL attributes of the th element must reflect the respective content attributes of the same name.

partial interface HTMLAreaElement {
  [CEReactions] attribute boolean noHref;
};

The noHref IDL attribute of the area element must reflect the element’s nohref content attribute.

partial interface HTMLBodyElement {
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString text;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString link;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString vLink;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString aLink;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString bgColor;
  attribute DOMString background;
};

The text IDL attribute of the body element must reflect the element’s text content attribute.

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 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.)

partial interface HTMLBRElement {
  [CEReactions] attribute DOMString clear;
};

The clear IDL attribute of the br element must reflect the content attribute of the same name.

partial interface HTMLTableCaptionElement {
  [CEReactions] attribute DOMString align;
};

The align IDL attribute of the caption element must reflect the content attribute of the same name.

partial interface HTMLTableColElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString ch;
  [CEReactions] attribute DOMString chOff;
  [CEReactions] attribute DOMString vAlign;
  [CEReactions] attribute DOMString width;
};

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.

User agents must treat dir elements in a manner equivalent to ul elements in terms of semantics and for purposes of rendering.

The dir element must implement the HTMLDirectoryElement interface.

[HTMLConstructor]
interface HTMLDirectoryElement : HTMLElement {
  [CEReactions] attribute boolean compact;
};

The compact IDL attribute of the dir element must reflect the content attribute of the same name.

partial interface HTMLDivElement {
  [CEReactions] attribute DOMString align;
};

The align IDL attribute of the div element must reflect the content attribute of the same name.

partial interface HTMLDListElement {
  [CEReactions] attribute boolean compact;
};

The compact IDL attribute of the dl element must reflect the content attribute of the same name.

partial interface HTMLEmbedElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString name;
};

The name and align IDL attributes of the embed element must reflect the respective content attributes of the same name.

The font element must implement the HTMLFontElement interface.

[HTMLConstructor]
interface HTMLFontElement : HTMLElement {
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString color;
  [CEReactions] attribute DOMString face;
  [CEReactions] attribute DOMString size;
};

The color, face, and size IDL attributes of the font element must reflect the respective content attributes of the same name.

partial interface HTMLHeadingElement {
  [CEReactions] attribute DOMString align;
};

The align IDL attribute of the h1–h6 elements must reflect the content attribute of the same name.

The profile IDL attribute on head elements (with the HTMLHeadElement interface) is intentionally omitted. Unless so required by another applicable specification, implementations would therefore not support this attribute. (It is mentioned here as it was defined in a previous version of the DOM specifications.)

partial interface HTMLHRElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString color;
  [CEReactions] attribute boolean noShade;
  [CEReactions] attribute DOMString size;
  [CEReactions] attribute DOMString width;
};

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.

partial interface HTMLHtmlElement {
  [CEReactions] attribute DOMString version;
};

The version IDL attribute of the html element must reflect the content attribute of the same name.

partial interface HTMLIFrameElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString scrolling;
  [CEReactions] attribute DOMString frameBorder;
  [CEReactions] attribute USVString longDesc;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString marginHeight;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString marginWidth;
};

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.

partial interface HTMLImageElement {
  [CEReactions] attribute DOMString name;
  [CEReactions] attribute USVString lowsrc;
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute unsigned long hspace;
  [CEReactions] attribute unsigned long vspace;

  [CEReactions, TreatNullAs=EmptyString] attribute DOMString border;
};

The name, align, border, hspace, and vspace IDL attributes of the img element must reflect the respective content attributes of the same name.

The lowsrc IDL attribute of the img element must reflect the element’s lowsrc content attribute, which for the purposes of reflection is defined as containing a URL.

partial interface HTMLInputElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString useMap;
};

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.

partial interface HTMLLegendElement {
  [CEReactions] attribute DOMString align;
};

The align IDL attribute of the legend element must reflect the content attribute of the same name.

partial interface HTMLLIElement {
  [CEReactions] attribute DOMString type;
};

The type IDL attribute of the li element must reflect the content attribute of the same name.

partial interface HTMLLinkElement {
  [CEReactions] attribute DOMString charset;
  [CEReactions] attribute DOMString target;
};

The charset and target IDL attributes of the link element must reflect the respective content attributes of the same name.

User agents must treat listing elements in a manner equivalent to pre elements in terms of semantics and for purposes of rendering.

partial interface HTMLMenuElement {
  [CEReactions] attribute boolean compact;
};

The compact IDL attribute of the menu element must reflect the content attribute of the same name.

partial interface HTMLMetaElement {
  [CEReactions] attribute DOMString scheme;
};

User agents may treat the scheme content attribute on the meta element as an extension of the element’s name content attribute when processing a meta element with a name attribute whose value is one that the user agent recognizes as supporting the scheme attribute.

User agents are encouraged to ignore the scheme attribute and instead process the value given to the metadata name as if it had been specified for each expected value of the scheme attribute.

For example, if the user agent acts on meta elements with name attributes having the value "eGMS.subject.keyword", and knows that the scheme attribute is used with this metadata name, then it could take the scheme attribute into account, acting as if it was an extension of the name attribute. Thus the following two meta elements could be treated as two elements giving values for two different metadata names, one consisting of a combination of "eGMS.subject.keyword" and "LGCL", and the other consisting of a combination of "eGMS.subject.keyword" and "ORLY":

<!-- this markup is invalid -->
<meta name="eGMS.subject.keyword" scheme="LGCL" content="Abandoned vehicles">
<meta name="eGMS.subject.keyword" scheme="ORLY" content="Mah car: kthxbye">

The suggested processing of this markup, however, would be equivalent to the following:

<meta name="eGMS.subject.keyword" content="Abandoned vehicles">
<meta name="eGMS.subject.keyword" content="Mah car: kthxbye">

The scheme IDL attribute of the meta element must reflect the content attribute of the same name.

partial interface HTMLObjectElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString archive;
  [CEReactions] attribute DOMString code;
  [CEReactions] attribute boolean declare;
  [CEReactions] attribute unsigned long hspace;
  [CEReactions] attribute DOMString standby;
  [CEReactions] attribute unsigned long vspace;
  [CEReactions] attribute DOMString codeBase;
  [CEReactions] attribute DOMString codeType;

  [CEReactions, TreatNullAs=EmptyString] attribute DOMString border;
};

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.

partial interface HTMLOListElement {
  [CEReactions] attribute boolean compact;
};

The compact IDL attribute of the ol element must reflect the content attribute of the same name.

partial interface HTMLParagraphElement {
  [CEReactions] attribute DOMString align;
};

The align IDL attribute of the p element must reflect the content attribute of the same name.

partial interface HTMLParamElement {
  [CEReactions] attribute DOMString type;
  [CEReactions] attribute DOMString valueType;
};

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.

User agents must treat plaintext elements in a manner equivalent to pre elements in terms of semantics and for purposes of rendering. (The parser has special behavior for this element, though.)

partial interface HTMLPreElement {
  [CEReactions] attribute long width;
};

The width IDL attribute of the pre element must reflect the content attribute of the same name.

partial interface HTMLScriptElement {
  [CEReactions] attribute DOMString event;
  [CEReactions] attribute DOMString htmlFor;
};

The event IDL attribute of the script element must reflect the element’s event content attribute.

The htmlFor IDL attribute of the script element must reflect the element’s for content attribute.

partial interface HTMLTableElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString border;
  [CEReactions] attribute DOMString frame;
  [CEReactions] attribute DOMString rules;
  [CEReactions] attribute DOMString summary;
  [CEReactions] attribute DOMString width;

  [CEReactions, TreatNullAs=EmptyString] attribute DOMString bgColor;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString cellPadding;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString cellSpacing;
};

The align, border, 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.

partial interface HTMLTableSectionElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString ch;
  [CEReactions] attribute DOMString chOff;
  [CEReactions] attribute DOMString vAlign;
};

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.

partial interface HTMLTableCellElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString axis;
  [CEReactions] attribute DOMString height;
  [CEReactions] attribute DOMString width;

  [CEReactions] attribute DOMString ch;
  [CEReactions] attribute DOMString chOff;
  [CEReactions] attribute boolean noWrap;
  [CEReactions] attribute DOMString vAlign;

  [CEReactions, TreatNullAs=EmptyString] attribute DOMString bgColor;
};

The align, axis, height, and width IDL attributes of the td and th elements must reflect the respective content attributes of the same name.

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 elements must reflect the elements' valign content attributes.

The bgColor IDL attribute of the td and th elements must reflect the elements' bgcolor content attributes.

partial interface HTMLTableRowElement {
  [CEReactions] attribute DOMString align;
  [CEReactions] attribute DOMString ch;
  [CEReactions] attribute DOMString chOff;
  [CEReactions] attribute DOMString vAlign;

  [CEReactions, TreatNullAs=EmptyString] attribute DOMString bgColor;
};

The align IDL attribute of the tr element must reflect the content attribute of the same name.

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 bgColor IDL attribute of the tr element must reflect the element’s bgcolor content attribute.

partial interface HTMLUListElement {
  [CEReactions] attribute boolean compact;
  [CEReactions] attribute DOMString type;
};

The compact and type IDL attributes of the ul element must reflect the respective content attributes of the same name.

User agents must treat xmp elements in a manner equivalent to pre elements in terms of semantics and for purposes of rendering. (The parser has special behavior for this element though.)

partial interface Document {
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString fgColor;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString linkColor;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString vlinkColor;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString alinkColor;
  [CEReactions, TreatNullAs=EmptyString] attribute DOMString bgColor;

  [SameObject] readonly attribute HTMLCollection anchors;
  [SameObject] readonly attribute HTMLCollection applets;

  void clear();
  void captureEvents();
  void releaseEvents();

  [SameObject] readonly attribute HTMLAllCollection all;
};

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.

IDL attribute	Content attribute
`fgColor`	`text`
`linkColor`	`link`
`vlinkColor`	`vlink`
`alinkColor`	`alink`
`bgColor`	`bgcolor`

The anchors attribute must return an HTMLCollection rooted at the Document node, whose filter matches only a elements with name attributes.

The applets attribute must return an HTMLCollection rooted at the Document node, whose filter matches only applet elements.

The clear(), captureEvents(), and releaseEvents() methods must do nothing.

The all attribute must return an HTMLAllCollection rooted at the Document node, whose filter matches all elements.

The object returned for all has several unusual behaviors:

The user agent must act as if the ToBoolean abstract operator in JavaScript converts the object returned for all to the false value.
The user agent must act as if the Abstract Equality Comparison algorithm, when given the object returned for all, returns true when compared to the undefined and null values. (Comparisons using the Strict Equality Comparison algorithm, and Abstract Equality comparisons to other values such as strings or objects, are unaffected.)
The user agent must act such that the typeof operator in JavaScript returns the string undefined when applied to the object returned for all.

These requirements are a willful violation of the JavaScript specification current at the time of writing. The JavaScript specification requires that ToBoolean return true for all objects to the true value, and does not have provisions for objects acting as if they were undefined for the purposes of certain operators. This violation is motivated by a desire for compatibility with two classes of legacy content: one that uses the presence of document.all as a way to detect legacy user agents, and one that only supports those legacy user agents and uses the document.all object without testing for its presence first. [ECMA-262]

partial interface Window {
  void captureEvents();
  void releaseEvents();

  [Replaceable, SameObject] readonly attribute External external;
};

The captureEvents() and releaseEvents() methods must do nothing.

The external attribute of the Window interface must return an instance of the External interface:

[NoInterfaceObject]
interface External {
  void AddSearchProvider();
  void IsSearchProviderInstalled();
};

The AddSearchProvider() and IsSearchProviderInstalled() methods must do nothing.

11.3.4.1. Plugins

This feature is in the process of being removed from the Web platform. (This is a long process that takes many years.) Using the plugins API at this time is highly discouraged.

Navigator implements NavigatorPlugins;

[NoInterfaceObject]
  interface NavigatorPlugins {
  [SameObject] readonly attribute PluginArray plugins;
  [SameObject] readonly attribute MimeTypeArray mimeTypes;
  boolean javaEnabled();
};

interface PluginArray {
  void refresh(optional boolean reload = false);
  readonly attribute unsigned long length;
  getter Plugin? item(unsigned long index);
  getter Plugin? namedItem(DOMString name);
};

interface MimeTypeArray {
  readonly attribute unsigned long length;
  getter MimeType? item(unsigned long index);
  getter MimeType? namedItem(DOMString name);
};

interface Plugin {
  readonly attribute DOMString name;
  readonly attribute DOMString description;
  readonly attribute DOMString filename;
  readonly attribute unsigned long length;
  getter MimeType? item(unsigned long index);
  getter MimeType? namedItem(DOMString name);
};

interface MimeType {
  readonly attribute DOMString type;
  readonly attribute DOMString description;
  readonly attribute DOMString suffixes; // comma-separated
  readonly attribute Plugin enabledPlugin;
};

The plugins attribute must return a PluginArray object.

The mimeTypes attribute must return a MimeTypeArray object.

A PluginArray object represents none, some, or all of the plugins supported by the user agent, each of which is represented by a Plugin object. Each of these Plugin objects may be hidden plugins. A hidden plugin can’t be enumerated, but can still be inspected by using its name.

The fewer plugins are represented by the PluginArray object, and of those, the more that are hidden, the more the user’s privacy will be protected. Each exposed plugin increases the number of bits that can be derived for fingerprinting. Hiding a plugin helps, but unless it is an extremely rare plugin, it is likely that a site attempting to derive the list of plugins can still determine whether the plugin is supported or not by probing for it by name (the names of popular plugins are widely known). Therefore not exposing a plugin at all is preferred. Unfortunately, many legacy sites use this feature to determine, for example, which plugin to use to play video. Not exposing any plugins at all might therefore not be entirely plausible.

The PluginArray objects created by a user agent must not be live. The set of plugins represented by the objects must not change once an object is created, except when it is updated by the refresh() method.

Each plugin represented by a PluginArray can support a number of MIME types. For each such plugin, the user agent must pick one or more of these MIME types to be those that are explicitly supported.

The explicitly supported MIME types of a plugin are those that are exposed through the Plugin and MimeTypeArray interfaces. As with plugins themselves, any variation between users regarding what is exposed allows sites to fingerprint users. User agents are therefore encouraged to expose the same MIME types for all users of a plugin, regardless of the actual types supported... at least, within the constraints imposed by compatibility with legacy content.

The supported property indices of a PluginArray object are the numbers from zero to the number of non-hidden plugins represented by the object, if any.

The length attribute must return the number of non-hidden plugins represented by the object.

The item() method of a PluginArray object must return null if the argument is not one of the object’s supported property indices, and otherwise must return the result of running the following steps, using the method’s argument as index:

Let list be the Plugin objects representing the non-hidden plugins represented by the PluginArray object.
Sort list alphabetically by the name of each Plugin.
Return the indexth entry in list.

It is important for privacy that the order of plugins not leak additional information, e.g., the order in which plugins were installed.

The supported property names of a PluginArray object are the values of the name attributes of all the Plugin objects represented by the PluginArray object. The properties exposed in this way must be unenumerable.

The namedItem() method of a PluginArray object must return null if the argument is not one of the object’s supported property names, and otherwise must return the Plugin object, of those represented by the PluginArray object, that has a name equal to the method’s argument.

The refresh() method of the PluginArray object of a Navigator object, when invoked, must check to see if any plugins have been installed or reconfigured since the user agent created the PluginArray object. If so, and the method’s argument is true, then the user agent must act as if the location.reload() method was called instead. Otherwise, the user agent must update the PluginArray object and MimeTypeArray object created for attributes of that Navigator object, and the Plugin and MimeType objects created for those PluginArray and MimeTypeArray objects, using the same Plugin objects for cases where the name is the same, and the same MimeType objects for cases where the type is the same, and creating new objects for cases where there were no matching objects immediately prior to the refresh() call. Old Plugin and MimeType objects must continue to return the same values that they had prior to the update, though naturally now the data is stale and may appear inconsistent (for example, an old MimeType entry might list as its enabledPlugin a Plugin object that no longer lists that MimeType as a supported MimeType).

A MimeTypeArray object represents the MIME types explicitly supported by plugins supported by the user agent, each of which is represented by a MimeType object.

The MimeTypeArray objects created by a user agent must not be live. The set of MIME types represented by the objects must not change once an object is created, except when it is updated by the PluginArray object’s refresh() method.

The supported property indices of a MimeTypeArray object are the numbers from zero to the number of MIME types explicitly supported by non-hidden plugins represented by the corresponding PluginArray object, if any.

The length attribute must return the number of MIME types explicitly supported by non-hidden plugins represented by the corresponding PluginArray object, if any.

The item() method of a MimeTypeArray object must return null if the argument is not one of the object’s supported property indices, and otherwise must return the result of running the following steps, using the method’s argument as index:

Let list be the MimeType objects representing the MIME types explicitly supported by non-hidden plugins represented by the corresponding PluginArray object, if any.
Sort list alphabetically by the type of each MimeType.
Return the indexth entry in list.

It is important for privacy that the order of MIME types not leak additional information, e.g., the order in which plugins were installed.

The supported property names of a MimeTypeArray object are the values of the type attributes of all the MimeType objects represented by the MimeTypeArray object. The properties exposed in this way must be unenumerable.

The namedItem() method of a MimeTypeArray object must return null if the argument is not one of the object’s supported property names, and otherwise must return the MimeType object that has a type equal to the method’s argument.

A Plugin object represents a plugin. It has several attributes to provide details about the plugin, and can be enumerated to obtain the list of MIME types that it explicitly supports.

The Plugin objects created by a user agent must not be live. The set of MIME types represented by the objects, and the values of the objects' attributes, must not change once an object is created, except when updated by the PluginArray object’s refresh() method.

The reported MIME types for a Plugin object are the MIME types explicitly supported by the corresponding plugin when this object was last created or updated by PluginArray.refresh(), whichever happened most recently.

The supported property indices of a Plugin object are the numbers from zero to the number of reported MIME types.

The length attribute must return the number of reported MIME types.

The item() method of a Plugin object must return null if the argument is not one of the object’s supported property indices, and otherwise must return the result of running the following steps, using the method’s argument as index:

Let list be the MimeType objects representing the reported MIME types.
Sort list alphabetically by the type of each MimeType.
Return the indexth entry in list.

It is important for privacy that the order of MIME types not leak additional information, e.g., the order in which plugins were installed.

The supported property names of a Plugin object are the values of the type attributes of the MimeType objects representing the reported MIME types. The properties exposed in this way must be unenumerable.

The namedItem() method of a Plugin object must return null if the argument is not one of the object’s supported property names, and otherwise must return the MimeType object that has a type equal to the method’s argument.

The name attribute must return the plugin’s name.

The description and filename attributes must return user-agent-defined (or, in all likelihood, plugin-defined) strings. In each case, the same string must be returned each time, except that the strings returned may change when the PluginArray.refresh() method updates the object.

If the values returned by the description or filename attributes vary between versions of a plugin, they can be used both as a fingerprinting vector and, even more importantly, as a trivial way to determine what security vulnerabilities a plugin (and thus a browser) may have. It is thus highly recommended that the description attribute just return the same value as the name attribute, and that the filename attribute return the empty string.

A MimeType object represents a MIME type that is, or was, explicitly supported by a plugin.

The MimeType objects created by a user agent must not be live. The values of the objects' attributes must not change once an object is created, except when updated by the PluginArray object’s refresh() method.

The type attribute must return the valid MIME type with no parameters describing the MIME type.

The description and suffixes attributes must return user-agent-defined (or, in all likelihood, plugin-defined) strings. In each case, the same string must be returned each time, except that the strings returned may change when the PluginArray.refresh() method updates the object.

If the values returned by the description or suffixes attributes vary between versions of a plugin, they can be used both as a fingerprinting vector and, even more importantly, as a trivial way to determine what security vulnerabilities a plugin (and thus a browser) may have. It is thus highly recommended that the description attribute just return the same value as the type attribute, and that the suffixes attribute return the empty string.

Commas in the suffixes attribute are interpreted as separating subsequent filename extensions, as in "htm,html".

The enabledPlugin attribute must return the Plugin object that represents the plugin that explicitly supported the MIME type that this MimeType object represents when this object was last created or updated by PluginArray.refresh(), whichever happened most recently.

The javaEnabled() attribute must return true if the user agent supports a plugin that supports the MIME type "application/x-java-vm"; otherwise it must return false.