HTML predefined icon-like symbols
W3C Working Draft 29 Jul 1996
Bert Bos <email@example.com>
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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.
What is standardized and what isn't?
Detailed description of the entities
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
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
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
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.
Desriptions of the entites, with suggested renderings. The part
`[test: xxx]' shows the entity in actual use.
&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.
) [test: &audio;]
&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.
&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.
&uuencoded.document; - uuencoded document
&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.
&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.
) [test: &text.document;]
&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.
) [test: &document;]
&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.
&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.
) [test: &caution;]
&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.
) [test: &film;]
&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.
) [test: &folder;]
&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.
) [test: &ftp;]
&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
&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.
) [test: ℑ]
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.
) [test: &index;]
&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.
) [test: &next;]
&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.
) [test: &previous;]
&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
&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
) [test: &telnet;]
&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
&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
&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
) [test: &new;]
&new; - new! Draws attention to something in the document
that has recently been changed and that the reader has probably not seen
&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.stop; - stop play. Stop button for stopping a movie
or sound, as on cassette or CD player (cf. play.start, play.pause,
&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; - 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).
) [test: &work;]
&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.
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
<firstname.lastname@example.org> (additions), Kevin Hughes
<email@example.com> (several shapes, color icons), Dave Raggett
<firstname.lastname@example.org> (integration into HTML3), Roy Fielding
<email@example.com> (cleaning up some of the bitmaps), Andy
Polyakov (color icons).
Bert Bos, 31 Jan 1996