HTML predefined icon-like symbols
W3C Working Draft 15 Feb 1996
Bert Bos
<bert@w3.org>
Status of this document
This is a W3C Working Draft for review by W3C members and other
interested parties. It is a draft document and may be updated,
replaced or obsoleted by other documents at any time. It is
inappropriate to use W3C Working Drafts as reference material or
to cite them as other than "work in progress". A list of current
W3C tech reports can be found at:
http://www.w3.org/pub/WWW/TR/
Note: since working drafts are subject to frequent
change, you are advised to reference the above URL, rather than
the URLs for working drafts themselves.
Abstract
One of the features of HTML is that it allows authors to
include characters and symbols in the text that cannot be typed
in. In HTML2, these so-called character entities are
limited to letters with accents and some typographic symbols.
HTML doesn't yet allow character entities for mathematical
symbols and other common signs. Authors have to resort to inline
images for these. This document defines a list of some of those `other'
symbols for use in future versions of HTML.
Contents
- Introduction
- Rationale
- What is standardized and what isn't?
- Detailed description of the entities
- Acknowledgments
- Copyright
HTML is a simple markup language for creating hypertext
documents that are portable between platforms. A document that
is marked-up with HTML consists of a mix of data characters (the
text that appears on the screen) and mark-up (information for
the application about the function and relation of the various
data parts).
Many data characters can be typed in directly: an `a' is just
the `a' key on the keyboard; for others the editor or
word-processor may have a special method to insert them: " + a = ä.
If the editor doesn't offer such a method, it may be possible to
replace the character with a bit of mark-up: type the six
characters `ä' instead of `ä' Any application that
understands HTML should be able to translate this back to the
appropriate character. A keyword like `ä' is called a
character entity (or more precise: `character entity
reference')
HTML2 defines a list of such character entities. That lists
consists of all the characters from the so-called ISO Added
Latin 1 set, plus a few of its own. This is enough for
texts in most Western languages, but it doesn't help with other
languages or mathematics. It is expected that the set will be
extended with all the characters in the ISO 10646
(a.k.a. Unicode) set, but even then there are many
common symbols that are missing.
HTML documents often contain small icons to draw attention to
interesting links or to special types of information. For
example, the existence of a sound could be indicated by an icon
of a loudspeaker. Gopher and FTP menus also use icons to
indicate the types of links they contain.
Such icons could be created with inline images, but there are
several advantages to incorporating them into future levels of
the HTML language in the form of SGML entities. In that way,
they are defined on a par with other predefined entities, such
as the ISO-defined sets of accented characters or the
mathematical and Greek symbols.
One advantage is that authors do not have to hunt around for
suitable images and create hyperlinks to them. Instead, they can
write &audio; and be assured that all browsers will
do their best to print some likeness of a loudspeaker.
Since the entity defines only the general shape, not the exact
pixel-for-pixel image, the browser is free to choose a size and
color that matches the rest of the display. The best browsers
will have symbols in several sizes, appropriate for use in 12,
14 or 17 point text, for example.
Using entities instead of inlined images is also faster
(depending on the implementation, of course). The browser will
always use the same image for an entity, independent of the
document's origin. After a while, there will even be browsers
that come with the symbols already built-in.
Authors are free to use any symbol for whatever purpose they
choose, but like Humpty Dumpty, they will be better understood
if they do not make a symbol mean what they choose it to mean,
but use it for its commonly accepted value. The descriptions
below suggest possible semantics, but only frequent usage by
many people can make the true intention clear.
First of all, of course, the names of the entities are
standardized.
Their intended use is also standardized, but the definitions
are kept somewhat vague on purpose. As stated above, the meaning of
a
symbol is likely to evolve when it comes into common usage,
until some universally accepted meaning emerges.
The shapes are not standardiazed, but the images in this
document are provided as suggestions, to give consistency across
implementations. Developers of products on specific platforms
are encouraged to use the conventional icons on that platform
where they exist.
The alternative glyphs below are there mainly to show that the shapes
can be varied.
-
- &archive; - archive server. A collection of
(related) documents, that can be manipulated as a single
unit. When it is used in a link, it retrieves either the
whole archive or its table of contents. Example:
Tar files, Zip files, database files.
- (or:
, or:
)
- &audio; - audio sequence. A sound fragment,
such as a piece of music or speech. When used in a link, it
will play the sound. Example: links to audio files
in Gopher menus; the current time in a synthesized voice.
- (or:
)
- &binary.document; - binary data. A document
that contains data that is unreadable by humans, and of
which the precise type is not known or not important. When
used in a link, the data is downloaded, but not displayed.
Example: binary files in Gopher menus.
- (or:
)
- &uuencoded.document; - uuencoded document
- (or:
)
- &binhex.document; - binhex format. A document
that is encoded in Macintosh hexadecimal coding. Hopefully
this symbol can be phased out in the future, as servers and
client become smarter, since this is not information that
normal users are interested in. Example: Binhex
files in Gopher menus.
- (or:
)
- &compressed.document; - compressed document. A
file that is compressed with compress,
gzip, or equivalent utilities. Normally part of a
link to such a file. Example: a compressed file in
an FTP directory.
- (or:
, or:
)
- &text.document; - text/plain, html, etc.. A
document containing primarily text. This includes text with
markup instructions, if the browser is (expected to be) able
to interpret them. A part of a link, it will retrieve and
display the document. Example: a plain text file,
an HTML document, a TeX DVI file.
- (or:
)
- &document; - unspecified document type. Some
document, the exact type of which is unimportant (contrast
this with &unknown.document; below).
Example: a directory listing showing files and
subdirectories (folders); a list of titles of articles, with
document symbols replacing bullet marks.
- (or:
)
- &unknown.document; - unrecognized document type
-
- &calculator; - calculator. This symbol should
give access to some sort of interactive calculator.
Example: a calculator could be included in a form
to allow people to do some computations before they fill in
the requested numbers.
- (or:
, or:
)
- &caution; - warning sign. Draws attention to an
important piece of information. It is normally not used in a
link. Example: `Warning: the next video fragment
contains scenes of extreme cruelty.'
-
- &clock; - clock or time. A clock should give access
to the current time or to the elapsed time since some event.
Example: selecting the clock returns the simulated
time in a multi-user strategy game.
-
- &disk.drive; - removable media type. Gives
access to whatever disk is in the indicated drive. The fact
that it is removable means that the contents can change or
may be absent altogether. Example: a link to the
disk on the machine of a colleague.
-
- &diskette; - floppy disk. Represents a
collection of files stored on a floppy disk. In contrast to
the &disk.drive; above, this is a specific disk.
Usually, access is slow. Example: a disk in a
jukebox, a disk in a mail-order catalogue.
-
- &display; - computer screen. The computer's
display as an output device. Could be used together with the
fax and the printer to let the user select where he want
something to be printed. Example: when a document
is available in different resolutions, the display symbol
indicates that one of them version is suitable for computer
screens.
-
- &fax; - facsimile machine. A fax machine as an
output device. Like the display and printer symbols, this
can be used to indicate the destination of some output.
Example: forwarding a message to somebody without
an e-mail address can be done by selecting the fax symbol
and entering a phone number.
-
- &filing.cabinet; - filing cabinet. A container
for documents and folders. It is usually larger than a
folder, and the contents are more divers. Example:
a link to an FTP server.
- (or:
)
- &film; - film or animation, such as MPEG movie. A timed
sequence of images, optionally with a sound track,
such as a video sequence, a computer animation, a slide
show, or a live video link. Example: a video clip
on a CD-I.
-
- &fixed.disk; - fixed media drive. Either a
container for folders and documents, or the destination of
some data. In the first case, there must be a reason why the
device is important (and therefore why the symbols for
folder or filing cabinet are not applicable).
Example: a link to the local files on the user's
own machine.
- (or:
, or:
)
- &folder; - folder or directory. A container for
documents and maybe other folders. As part of a link, it
should retrieve a listing of the folder's contents.
Example: a gopher menu, a directory.
-
- &form; - fill-out form. Gives access to a
fill-out form, normally coded as an HTML document.
Example: links to different types of tax forms.
- (or:
)
- &ftp; - ftp server. Represents a connection
using the FTP protocol, when for some reason it is important
that the user is aware of the server's type.
Example: information that is available over a
number of channels, one of which is an FTP connection.
-
- &glossary; - glossary of terms, etc. Gives
access to a glossary of terms. Example: a link to a
technical dictionary.
-
- &gopher; - gopher server. A connection using
the Gopher protocol. Example: an information
provider might list alternative addresses, indicating with
the gopher symbol that some of them are Gopher connections.
-
- &home; - home document. Represents the `home
page' of a collection of related nodes (not necessarily the
user's own home page). Normally part of a hyperlink.
Example: each node in somebody's personal
collection could contain a link to his `Welcome' page.
- (or:
, or:
, or:
)
- ℑ - photograph, drawing or graphic of any
kind. Represents a photograph, drawing, etc. When used in a
link, it retrieves the image and displays it.
Example: a link of type I in a Gopher menu; a
`submit' button in a form that sets image parameters.
- (or:
)
- &index; - searchable index. Represents an
interactive index. When used in a link, it gives access to a
searchable document, which allows at least keywords to be
entered. Example: a link to a WAIS index over some
collection of documents; a link of type 7 in a Gopher menu.
-
- &mail; - e-mail messages . Represents either a
single mail message or the mail sub-system. If the context
is clear, it can also be used as a label in front of
someone's address (cf. the telephone symbol). As part of a
hyperlink, it respectively retrieves that message or starts
a (possibly integrated) mail agent. Example: in a
view of a mailbox, each message can be prefixed with a mail
icon.
-
- &mail.in; - mail-in tray. A special mail
folder (viz. the one in which the mail system deposits new
messages). As a hyperlink, it displays the contents of the
folder, in the form of an index.
-
- &mail.out; - mail-out tray. A special mail
folder (viz. the one in which the user stores messages that
are to be sent out). Note that this is not the
folder that keeps copies of messages that have been sent.
Example: a link to a special directory in which the
user's composed messages are collected, until he exits the
mail system (at which point the messages are sent and the
directory is emptied.)
-
- ↦ - geographical or schematic map. A
document that consists of a map of some kind. In a link, it
retrieves the map and displays it. Example: a road
map with instructions how to reach some building; a
schematic representation of some production process.
-
- &mouse; - mouse/pointing device. The mouse as
an input device. Example: label in front of
instructions that are only applicable if you have a mouse.
-
-
- ¬ebook; - notes or annotations. Indicates
the presence of notes or annotations, presumably related to
the context of the icon. When part of a link, it displays
the notes. Example: an annotated classical text
linking the commentary by means of symbols in the margin.
-
- &parent; - parent of current document. In a
more or less hierarchical collection of nodes, this
represents the parent of the current node. Should be used as
a link to that node. Example: a link to the parent
directory of an FTP directory.
- (or:
)
- &next; - next document in current sequence.
The next document of a collection that is meant to be read
in order. Example: each chapter of a book could end
with a link to the next chapter.
- (or:
)
- &previous; - previous document in current
sequence. The previous document of a collection that is
meant to be read in order. Example: each chapter of
a book could start with a link to the previous chapter.
-
- &printer; - hardcopy device. A printer as an
output device. (Compare with the display and fax symbols.)
Example: ???
-
- &summary; - summary. A summary of a document
or of a collection of documents. In a link, it retrieves the
text of the summary. Example: the table of contents
of a book could include a link to a summary.
- (or:
, or:
)
- &telnet; - telnet connection. A terminal-based
connection to some service, using the Telnet protocol. When
part of a link, it should start a terminal-emulator and a
telnet connection to the indicated service.
Example: a link to a library's on-line catalogue
that still uses its own user-interface.
-
- &tn3270; - tn3270 terminal session. A
terminal-based connection to some service, that requires a
TN3270 terminal (-emulator) to work (cf. the telnet symbol).
When part of a link, it should start a terminal-emulator and
a telnet connection to the indicated service.
Example: a link to a database manager running on an
IBM mainframe.
-
- &toc; - table of contents. A table of contents
over one or more documents. As a link, it should display the
table of contents associated with the current document.
Example: each chapter of a hyper-book could start
with a link to the book's table of contents.
-
- &trash; - waste paper basket
-
- &telephone; - telephone number. Next to a
number, it indicates that the number represents a telephone
number (cf. the third meaning of the mail symbol).
-
- &cd.rom; - CD ROM. A collection of documents
contained on a read-only CD, including music CDs. (cf. the
fixed disk, disk drive, and diskette symbols).
-
- &cd.i - CD-I. An interactive session with a
CD-I.
-
- &keyboard; - keyboard device. The keyboard as
an input device (cf. mouse).
-
- &stop; - error sign. A more severe warning then
the &caution; symbol.
-
- &network; - computer network
-
- &smiley; - happy face. Used as postfix adjective/adverb,
meaning `for fun', `ironic', `half-serious', etc.
-
- &sadsmiley; - sad face. Used as postfix adverb, meaning
`unfortunately'
- (or:
)
- &new; - new! Draws attention to something in the
document that has recently been changed and that the
reader has probably not seen before.
-
- &play.start; - play. Play button for starting a movie
or
sound, as on cassette or CD player (cf. play.stop, play.pause,
play.fast.forward, play.fast.reverse).
-
- &play.stop; - stop play. Stop button for stopping a
movie or
sound, as on cassette or CD player (cf. play.start, play.pause,
play.fast.forward, play.fast.reverse).
-
- &play.pause; - pause. Pause button for pausing a movie
or
sound, as on cassette or CD player (cf. play.start, play.stop,
play.fast.forward, play.fast.reverse).
-
- &play.fast.forward; - fast forward. fast-forward button
for
skipping along a movie or sound, as on cassette or CD player
(cf. play.stop, play.pause, play.start, play.fast.reverse).
-
- &play.fast.reverse; - fast reverse. fast reverse button
for
going back in a movie or sound, as on cassette or CD player
(cf. play.stop, play.pause, play.start, play.fast.reverse).
- (or:
)
- &work; - work in progress/under construction. Often
added to a document that is in a very preliminary state. (The icon is based
on the traffic sign of a road worker and a heap of sand. In countries where
the sign is unknown or looks different, the entity may have to be displayed
with a different icon.)
-
- &www; - The World-Wide Web. To refer to the WWW as
a whole, to mark a URL, etc.
-
- &html; - HTML. Information about HTML, mark a document
as being in HTML, link to an HTML version, etc.
DTD fragment
As is usual with SGML entities defined as system data, the part
after `system' is arbitrary and should be redefined as
appropriate by implementations.
<!entity archive system "[archive ]">
<!entity audio system "[audio ]">
<!entity binary.document system "[binary.document ]">
<!entity binhex.document system "[binhex.document ]">
<!entity calculator system "[calculator ]">
<!entity caution system "[caution ]">
<!entity cd.i system "[cd.i ]">
<!entity cd.rom system "[cd.rom ]">
<!entity clock system "[clock ]">
<!entity compressed.document system "[compressed.document ]">
<!entity disk.drive system "[disk.drive ]">
<!entity diskette system "[diskette ]">
<!entity document system "[document ]">
<!entity fax system "[fax ]">
<!entity filing.cabinet system "[filing.cabinet ]">
<!entity film system "[film ]">
<!entity fixed.disk system "[fixed.disk ]">
<!entity folder system "[folder ]">
<!entity form system "[form ]">
<!entity ftp system "[ftp ]">
<!entity glossary system "[glossary ]">
<!entity gopher system "[gopher ]">
<!entity home system "[home ]">
<!entity html system "[html ]">
<!entity image system "[image ]">
<!entity index system "[index ]">
<!entity keyboard system "[keyboard ]">
<!entity mail system "[mail ]">
<!entity mail.in system "[mail.in ]">
<!entity mail.out system "[mail.out ]">
<!entity map system "[map ]">
<!entity mouse system "[mouse ]">
<!entity new system "[new ]">
<!entity next system "[next ]">
<!entity notebook system "[notebook ]">
<!entity parent system "[parent ]">
<!entity play.fast.forward system "[play.fast.forward ]">
<!entity play.fast.reverse system "[play.fast.reverse ]">
<!entity play.pause system "[play.pause ]">
<!entity play.start system "[play.start ]">
<!entity play.stop system "[play.stop ]">
<!entity previous system "[previous ]">
<!entity printer system "[printer ]">
<!entity sadsmiley system "[sadsmiley ]">
<!entity smiley system "[smiley ]">
<!entity stop system "[stop ]">
<!entity summary system "[summary ]">
<!entity telephone system "[telephone ]">
<!entity telnet system "[telnet ]">
<!entity text.document system "[text.document ]">
<!entity tn3270 system "[tn3270 ]">
<!entity toc system "[toc ]">
<!entity trash system "[trash ]">
<!entity unknown.document system "[unknown.document ]">
<!entity uuencoded.document system "[uuencoded.document ]">
<!entity work system "[work ]">
<!entity www system "[www ]">
The following people contributed in some way: William M.
Perry <wmperry@indiana.edu> (additions), Kevin
Hughes <kevinh@eit.com> (several shapes, color icons), Dave
Raggett <dsr@w3.org> (integration into
HTML3), Roy Fielding <fielding@ics.uci.edu>
(cleaning up some of the bitmaps), Andy Polyakov (color icons).
World-Wide Web
Consortium
Bert Bos, 31 Jan 1996