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INTERNET DRAFT February 8, 1995
Expires in six months
HyperText Markup Language Specification - 2.0
<draft-ietf-html-spec-01.txt>
STATUS OF THIS MEMO
This document is an Internet draft. Internet drafts are
working documents of the Internet Engineering Task Force
(IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet drafts.
Internet drafts are draft documents valid for a maximum
of six months and may be updated, replaced, or obsoleted
by other documents at any time. It is inappropriate to
use Internet drafts as reference material or to cite
them other than as "work in progress."
To learn the current status of any Internet-Draft,
please check the "1id-abstracts.txt" listing contained
in the Internet- Drafts Shadow Directories on
ftp.is.co.za (Africa), nic.nordu.net (Europe),
munnari.oz.au (Pacific Rim), ds.internic.net (US East
Coast), or ftp.isi.edu (US West Coast).
Distribution of this document is unlimited. Please send
comments to the HTML working group (HTML-WG) of the
Internet Engineering Task Force (IETF) at <html-
wg@oclc.org>. Discussions of the group are archived at
URL: http://www.acl.lanl.gov/HTML_WG/archives.html.
Abstract
The HyperText Markup Language (HTML) is a simple markup
language used to create hypertext documents that are
portable from one platform to another. HTML documents
are SGML documents with generic semantics that are
appropriate for representing information from a wide
range of applications. HTML markup can represent
hypertext news, mail, documentation, and hypermedia;
menus of options; database query results; simple
structured documents with in-lined graphics; and
hypertext views of existing bodies of information.
HTML has been in use by the World Wide Web (WWW) global
information initiative since 1990. This specification
roughly corresponds to the capabilities of HTML in
Berners-Lee, Connolly, et. al. Page 1
HTML 2.0 February 8, 1995
common use prior to June 1994. It is defined as an
application of ISO Standard 8879:1986 Information
Processing Text and Office Systems; Standard Generalized
Markup Language (SGML).
The "text/html; version=2.0" Internet Media Type (RFC 1590) and
MIME Content Type (RFC 1521) is defined by this specification.
Contents
Overview of HTML Specification........................ 2
HTML Specification.................................... 11
Security Considerations............................... 52
Obsolete and Proposed Features........................ 53
HTML Document Type Definitions........................ 56
Glossary.............................................. 74
References............................................ 77
Acknowledgments....................................... 78
Author's Addresses.................................... 80
1. Overview of HTML Specification
This chapter is a summary of the HTML specification. See
Section 2. for the complete specification.
HTML describes the structure and organization of a
document. It only suggests appropriate presentations of
the document when processed.
In HTML documents, tags define the start and end of
headings, paragraphs, lists, character highlighting and
links. Most HTML elements are identified in a document
as a start tag, which gives the element name and
attributes, followed by the content, followed by the end
tag. Start tags are delimited by < and >, and end tags
are delimited by </ and >.
Example:
Berners-Lee, Connolly, et. al. Page 2
HTML 2.0 February 8, 1995
<H1>This is a heading</H1>
Every HTML document starts with a HTML document
identifier which contains two sections, a head and a
body. The head contains HTML elements which describe the
documents title, usage and relationship with other
documents. The body contains other HTML elements with
the entire text and graphics of the document.
This overview briefly describes the syntax of HTML
elements and provides an example HTML document.
NOTE: The term "HTML user agent" is used in this
document to describe applications that are used with
HTML documents.
1.1 HTML Elements
1.1.1 Document Structure Elements
HTML Identifier
<HTML> ... </HTML>
The HTML identifier defines the document as containing
HTML elements. It contains only the Head and Body
elements.
Head
<HEAD> ... </HEAD>
The Head element contains HTML elements that describe
the documents title, usage and relationship with other
documents.
Body
<BODY> ... </BODY>
The Body element contains the text and its associated
HTML elements of the document.
Example of Document Structure Elements
<HTML>
<HEAD>
<TITLE>The Document's Title</TITLE>
</HEAD>
<BODY>
Berners-Lee, Connolly, et. al. Page 3
HTML 2.0 February 8, 1995
The document's text.
</BODY>
1.1.2 Anchor Element
Anchor
<A> ... </A>
An anchor specifies a link to another location (<A
HREF>) or the value to use when linking to this location
from another location (<A NAME>):
See <A HREF="http://www.hal.com/">HaL</A>'s
information for more details.
<A NAME="B">Section B</A> describes...
...
See <A HREF="#B">Section B</A> for more information.
1.1.3 Block Formatting Elements
Address
<ADDRESS> ... </ADDRESS>
<ADDRESS>
Newsletter editor<BR>
J.R. Brown<BR>
JimquickPost News, Jumquick, CT 01234<BR>
Tel (123) 456 7890
</ADDRESS>
Body
<BODY> ... </BODY>
Place the <BODY> and </BODY> tags above and below the
body of the text (not including the head) of your HTML
document.
Blockquote
<BLOCKQUOTE>... </BLOCKQUOTE>
I think it ends
<BLOCKQUOTE>
<P>Soft you now, the fair Ophelia. Nymph, in thy
orisons,
be all my sins remembered.
</BLOCKQUOTE>
Berners-Lee, Connolly, et. al. Page 4
HTML 2.0 February 8, 1995
but I am not sure.
Head
<HEAD> ... </HEAD>
Every HTML document must have a head, which provides a
title. Example:
<HTML>
<HEAD>
<TITLE>Introduction to HTML</TITLE>
</HEAD>
Headings
<H1>This is a first level heading</H1>
<P>There are six levels of headings.
<H2>Second level heading</H2>
<P>This text appears under the second level heading
Horizontal Rule
<HR>
Inserts a horizontal rule that spans the width of the
document. Example:
<HR>
<ADDRESS>February 8, 1995, CERN</ADDRESS>
</BODY>
HTML Identifier
<HTML> ... </HTML>
An HTML document begins with an <HTML> tag and ends with
the </HTML> tag.
Line Break
<BR>
Forces a line break:
Name<BR>
Street address<BR>
City, State Zip
Paragraph
Berners-Lee, Connolly, et. al. Page 5
HTML 2.0 February 8, 1995
<P> ... </P>
<H1>This Heading Precedes the Paragraph</H1>
<P>This is the text of the first paragraph.
<P>This is the text of the second paragraph. Although
you do not need to start paragraphs on new lines,
maintaining this convention facilitates document
maintenance.
<P>This is the text of a third paragraph.
Preformatted Text
<PRE> ... </PRE>
<PRE WIDTH="80">
This is an example of preformatted text.
</PRE>
Title
<TITLE> ... </TITLE>
<TITLE>Title of document</TITLE>
1.1.4 List Elements
Definition List
<DL> ... <DT>term<DD>definition... </DL>
<DL>
<DT>Term<DD>This is the first definition.
<DT>Term<DD>This is the second definition.
</DL>
Directory List
<DIR> ... <LI>List item... </DIR>
<DIR>
<LI>A-H<LI>I-M
<LI>M-R<LI>S-Z
</DIR>
Menu List
<MENU> ... <LI>List item... </MENU>
<MENU>
Berners-Lee, Connolly, et. al. Page 6
HTML 2.0 February 8, 1995
<LI>First item in the list.
<LI>Second item in the list.
<LI>Third item in the list.
</MENU>
Ordered List
<OL> ... <LI>List item... </OL>
<OL>
<LI>Click the Web button to open the Open the URL
window.
<LI>Enter the URL number in the text field of the Open
URL window. The Web document you specified is displayed.
<LI>Click highlighted text to move from one link to
another.
</OL>
Unordered List
<UL> ... <LI>List item... </UL>
<UL>
<LI>This is the first item in the list.
<LI>This is the second item in the list.
<LI>This is the third item in the list.
</UL>
1.1.5 Information Type and Character Formatting Elements
Bold
<B> ... </B>
Suggests the rendering of the text in boldface. If
boldface is not available, alternative mapping is
allowed.
Citation
<CITE> ... </CITE>
Specifies a citation; typically rendered as italic.
Code
<CODE> ... </CODE>
Indicates an inline example of code; typically rendered
as monospaced.. Do not confuse with the <PRE> tag.
Berners-Lee, Connolly, et. al. Page 7
HTML 2.0 February 8, 1995
Emphasis
<EM> ... </EM>
Provides typographic emphasis; typically rendered as
italics.
Italics
<I> ... </I>
Suggests the rendering of text in italic font, or
slanted if italic is not available.
Keyboard
<KBD> ... </KBD>
Indicates text typed by a user; typically rendered as
monospaced.
Sample
<SAMP> ... </SAMP>
Indicates a sequence of literal characters; typically
rendered as monospaced..
Strong
<STRONG> ... </STRONG>
Provides strong typographic emphasis; typically rendered
as bold.
Typetype
<TT> ... </TT>
Specifies that the text be rendered in fixed-width font.
Variable
<VAR> ... </VAR>
Indicates a variable name; typically rendered as italic.
1.1.6 Image Element
Berners-Lee, Connolly, et. al. Page 8
HTML 2.0 February 8, 1995
Image
<IMG>
Inserts the referenced graphic image into the document
at the location where the element occurs.
Example:
<IMG SRC ="triangle.gif" ALT="Warning:"> Be sure to read
these instructions.
1.1.7 Form Elements
Form
<FORM> ... </FORM>
The Form element contains nested elements (described
below) which define user input controls and allow
descriptive text to be displayed when the document is
processed.
Input
<INPUT>
Takes these attributes: ALIGN, MAXLENGTH, NAME, SIZE,
SRC, TYPE, VALUE. The type attribute can define these
field types: CHECKBOX, HIDDEN, IMAGE, PASSWORD, RADIO,
RESET, SUBMIT, TEXT.
Example:
<FORM METHOD="POST" action="http://www.hal.com/sample">
<P>Your name: <INPUT NAME="name" SIZE="48">
<P>Male <INPUT NAME="gender" TYPE=RADIO VALUE="male">
<P>Female <INPUT NAME="gender" TYPE=RADIO
VALUE="female">
</FORM>
Option
<OPTION>
The Option element can only occur within a Select
element. It represents one choice.
Select
Berners-Lee, Connolly, et. al. Page 9
HTML 2.0 February 8, 1995
<SELECT NAME="..." > ... </SELECT>
Select provides a list of choices.
<SELECT NAME="flavor">
<OPTION>Vanilla
<OPTION>Strawberry
<OPTION>Rum and Raisin
<OPTION>Peach and Orange
</SELECT>
Textarea
<TEXTAREA> ... </TEXTAREA>
Textarea defines a multi-line text entry input control.
It contains the initial text contents of the control.
<TEXTAREA NAME="address" ROWS=64 COLS=6>
HaL Computer Systems
1314 Dell Avenue
Campbell California 95008
</TEXTAREA>
1.1.8 Character Data in HTML
Representing Graphic Characters in HTML
Because of the way special characters are used in
marking up HTML text, character strings are used to
represent the less than (<) and greater than (>) symbols
and the ampersand (&) as shown in Section 2.17.1.
Representing Special Characters in HTML
HTML inherits both from SGML and from MIME in its description
of characters and character sets. The result is a small
amount of duplication of function: there are multiple ways to
code characters in HTML.
HTML documents are encoded in some character encoding;
the character encoding may be specified, for example,
by the "charset" parameter associated with the "text/html"
media type.
Independent of the character encoding used,
HTML also allows references to any of the ISO Latin-1
alphabet, using the names in the table ISO Latin-1
Character Representations, which is derived from ISO
Standard 8879:1986//ENTITIES Added Latin 1//EN. For
Berners-Lee, Connolly, et. al. Page 10
HTML 2.0 February 8, 1995
details, see 2.17.2.
1.2 Example HTML Document
<HTML>
<HEAD>
<TITLE>Structural Example</TITLE>
</HEAD>
<BODY>
<H1>First Header</H1>
<P>This is a paragraph in the example HTML file.
Keep in mind that the title does not appear in the
document text, but that the header (defined by H1) does.
<UL>
<LI>First item in an unordered list.
<LI>Second item in an unordered list.
</UL>
<P>This is an additional paragraph. Technically, end
tags
are not required for paragraphs, although they are
allowed.
You can include character highlighting in a paragraph.
<I>This sentence of the paragraph is in italics.</I>
<IMG SRC ="triangle.gif" alt="Warning:"> Be sure to read
these instructions.
</BODY>
</HTML>
2. HTML Specification
HTML has been in use by the World Wide Web (WWW) global
information initiative since 1990. This specification
corresponds to the legitimate capabilities of HTML in
common use prior to June 1994. It is defined as an
application of ISO Standard 8879:1986: Standard
Generalized Markup Language (SGML). This specification
is proposed as the Internet Media Type (RFC 1590) and
MIME Content Type (RFC 1521) called "text/html", or
"text/html; version=2.0".
This specification also includes:
- 5.1 SGML Declaration for HTML
- 5.1.1 Sample SGML Open Style Entity Catalog for HTML
- 5.2 HTML DTD
This specification is currently available on the World
Wide Web at URL: http://www.hal.com/%7Econnolly/html-spec
Berners-Lee, Connolly, et. al. Page 11
HTML 2.0 February 8, 1995
Please send comments to the discussion list at: html-
wg@oclc.org
2.1 Levels of Conformance
Version 2.0 of the HTML specification introduces forms
for user input of information, and adds a distinction
between levels of conformance:
Level 0
Indicates the minimum conformance level. When writing
Level 0 documents, authors can be confident that the
rendering at different sites will reflect their intent.
Level 1
Includes Level 0 features plus features such as
highlighting and images.
Level 2
Includes all Level 0 and Level 1 features, plus forms.
Features of higher levels, such as tables, figures, and
mathematical formulae, are under discussion and are
described as proposed where mentioned.
2.2 Undefined Tag and Attribute Names
An accepted networking principle is to be conservative
in that which one produces, and liberal in that which
one accepts. HTML user agents should be liberal except
when verifying code. HTML generators should generate
strictly conforming HTML.
The behavior of HTML user agents reading HTML documents
and discovering tag or attribute names which they do not
understand should be to behave as though, in the case of
a tag, the whole tag had not been there but its content
had, or in the case of an attribute, that the attribute
had not been present.
2.3 Deprecated and Recommended Sections in DTDs
In Section 5., optional "deprecated" and "recommended"
sections are used. Conformance with this specification
is defined with these sections disabled. In the liberal
spirit of Section 2.2, HTML user agents reading HTML
documents should accept syntax corresponding to the
Berners-Lee, Connolly, et. al. Page 12
HTML 2.0 February 8, 1995
specification with "deprecated" turned on. HTML user
agents generating HTML may in the spirit of
conservation, generate documents that conform to the
specification with the "recommended" sections turned on.
2.4 HTML as an Internet Media Type
This (and upward compatible specifications) define the Internet
Media Type (RFC 1590) and MIME Content Type (RFC 1521) called
"text/html".
The type "text/html" accepts the following parameters:
Level
The level parameter specifies the feature set used in
the document. The level is an integer number, implying
that any features of same or lower level may be present
in the document. Levels 0, 1 and 2 are defined by this
specification.
Version
To help avoid future compatibility problems, the version
parameter may be used to give the version number of the
specification to which the document conforms. The
version number appears at the front of this document and
within the public identifier for the SGML DTD. This
specification defines version 2.0.
Charset
The charset parameter (as defined in section 7.1.1 of
RFC 1521) may be used with the text/html to specify
the encoding used to represent the HTML document as
a sequence of bytes. Normally, text/* media types
specify a default value of US-ASCII for the charset
parameter. However, for text/html, if the byte stream
contains data that is not in the 7-bit US-ASCII set, the
HTML interpreting agent should assume a default charset of
ISO-8859-1.
When an HTML document is encoded using US-ASCII,
the mechanisms of numeric character references (see
Section 2.16.2) and character entity references (see
Section 2.16.3) may be used to encode additional characters
from ISO-8859-1.
Other values for the charset parameter are not defined
in this specification, but may be specified in future
Berners-Lee, Connolly, et. al. Page 13
HTML 2.0 February 8, 1995
levels or versions of HTML.
It is envisioned that HTML will use the charset parameter
to allow support for non-Latin characters such as
Greek, Arabic, Hebrew, Japanese, rather than relying on
any SGML mechanism for doing so.
2.5 Understanding HTML and SGML
HTML is an application of ISO Standard 8879:1986 -
Standard Generalized Markup Language (SGML). SGML is a
system for defining structured document types, and
markup languages to represent instances of those
document types. The SGML declaration for HTML is given
in Section 5.1. It is implicit among HTML user agents.
If the HTML specification and SGML standard conflict,
the SGML standard is definitive.
Every SGML document has three parts:
SGML declaration
Binds SGML processing quantities and syntax token names
to specific values. For example, the SGML declaration in
the HTML DTD specifies that the string that opens an end
tag is </ and the maximum length of a name is 72
characters.
Prologue
Includes one or more document type declarations, which
specify the element types, element relationships and
attributes.
Instance
Contains the data and markup of the document.
HTML refers to the document type as well as the markup
language for representing instances of that document
type.
2.6 Working with Structured Text
An HTML document is like a text file, except that some
of the characters are markup. Markup (tags) define the
structure of the document.
To identify information as HTML, each HTML document
Berners-Lee, Connolly, et. al. Page 14
HTML 2.0 February 8, 1995
should start with the prologue:
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN//2.0">
NOTE: If the body of a text/html body part does not
begin with a document type declaration, an HTML user
agent should infer the above document type declaration.
HTML documents should also contain an <HTML> tag at the
beginning of the file, after the prologue, and an
</HTML> tag at the end. Within those tags, an HTML
document is organized as a head and a body, much like
memo or a mail message. Within the head, you can specify
the title and other information about the document.
Within the body, you can structure text into paragraphs
and lists as well as highlighting phrases and creating
links. You do this using HTML elements.
NOTE: Technically, the start and end tags for HTML,
Head, and Body elements are omissible; however, this is
not recommended since the head/ body structure allows an
implementation to determine certain properties of a
document, such as the title, without parsing the entire
document.
2.6.1 HTML Elements
In HTML documents, tags define the start and end of
headings, paragraphs, lists, character highlighting and
links. Most HTML elements are identified in a document
as a start tag, which gives the element name and
attributes, followed by the content, followed by the end
tag. Start tags are delimited by < and >, and end tags
are delimited by </ and >.
Example:
<H1>This is a Heading</H1>
Some elements only have a start tag without an end tag.
For example, to create a line break, you use the <BR>
tag. Additionally, the end tags of some other elements,
such as Paragraph (<P>), List Item (<LI>), Definition
Term (<DT>), and Definition Description (<DD>) elements,
may be omitted.
The content of an element is a sequence of characters
and nested elements. Some elements, such as anchors,
cannot be nested. Anchors and character highlighting may
be put inside other constructs.
Berners-Lee, Connolly, et. al. Page 15
HTML 2.0 February 8, 1995
NOTE: The SGML declaration for HTML specifies SHORTTAG
YES, which means that there are other valid syntaxes for
tags, such as NET tags, <EM/.../; empty start tags, <>;
and empty end tags, </>. Until support for these idioms
is widely deployed, their use is strongly discouraged.
2.6.2 Names
A name consists of a letter followed by up to 71
letters, digits, periods, or hyphens. Element names are
not case sensitive, but entity names are. For example,
<BLOCKQUOTE>, <BlockQuote>, and <blockquote> are
equivalent, whereas & is different from &.
In a start tag, the element name must immediately follow
the tag open delimiter <.
2.6.3 Attributes
In a start tag, white space and attributes are allowed
between the element name and the closing delimiter. An
attribute typically consists of an attribute name, an
equal sign, and a value (although some attributes may be
just a value). White space is allowed around the equal
sign.
The value of the attribute may be either:
- A string literal, delimited by single quotes or
double quotes and not containing any occurrences of the
delimiting character.
- A name token (a sequence of letters, digits,
periods, or hyphens)
In this example, A is the element name, HREF is the
attribute name, and http://host/dir/file.html is the
attribute value:
<A HREF="http://host/dir/file.html">
NOTE: Some non-SGML implementations consider any
occurrence of the > character to signal the end of a
tag. For compatibility with such implementations, when >
appears in an attribute value, you may want to represent
it with an entity or numeric character reference (see
Section 2.17.1), such as: <IMG SRC="eq1.jpg" alt="a >
b">
Berners-Lee, Connolly, et. al. Page 16
HTML 2.0 February 8, 1995
To put quotes inside of quotes, you may use the
character representation " as in:
<IMG SRC="image.jpg" alt="First "real"
example">
The length of an attribute value is limited to 1024
characters after replacing entity and numeric character
references.
NOTE: Some non-SGML implementations allow any character
except space or > in a name token. Attributes values
must be quoted only if they don't satisfy the syntax for
a name token.
Attributes with a declared value of NAME, such as ISMAP
and COMPACT, may be written using a minimized syntax.
The markup:
<UL COMPACT="compact">
can be written using a minimized syntax:
<UL COMPACT>
NOTE: Some non-SGML implementations only understand the
minimized syntax.
2.6.4 Special Characters
Characters that are used to represent markup (such as
ampersand (&), lesser (<) and greater (>)) should themselves
be represented by markup, using either entity or numeric
character references. For more information, see
Section 2.16.
2.6.5 Comments
To include comments in an HTML document that will be
ignored by the HTML user agent, surround them with <!--
and -->. After the comment delimiter, all text up to the
next occurrence of --> is ignored. Hence comments cannot
be nested. White space is allowed between the closing --
and >, but not between the opening <! and --.
For example:
<HEAD>
<TITLE>HTML Guide: Recommended Usage</TITLE>
<!-- Id: Text.html,v 1.6 1994/04/25 17:33:48 connolly Exp -->
Berners-Lee, Connolly, et. al. Page 17
HTML 2.0 February 8, 1995
</HEAD>
NOTE: Some historical HTML user agents incorrectly
consider a > sign to terminate a comment.
2.7 The Head Element and Related Elements
Only certain elements are allowed in the head of an HTML
document. Elements that may be included in the head of a
document are:
2.7.1 Head
<HEAD> ... </HEAD>
Level 0
The head of an HTML document is an unordered collection
of information about the document. It requires the Title
element between <HEAD> and </HEAD> tags in this format:
<HEAD>
<TITLE>Introduction to HTML</TITLE>
</HEAD>
2.7.2 Base
Level 0
The Base element allows the URL of the document itself
to be recorded in situations in which the document may
be read out of context. URLs within the document may be
in a "partial" form relative to this base address.
Where the base address is not specified, the HTML user
agent uses the URL it used to access the document to
resolve any relative URLs.
The Base element has one attribute, HREF, which
identifies the URL.
2.7.3 Isindex
Level 0
The Isindex element tells the HTML user agent that the
document is an index document. As well as reading it,
the reader may use a keyword search.
The document can be queried with a keyword search by
Berners-Lee, Connolly, et. al. Page 18
HTML 2.0 February 8, 1995
adding a question mark to the end of the document
address, followed by a list of keywords separated by
plus signs.
NOTE: The Isindex element is usually generated
automatically by a server. If added manually to an HTML
document, the HTML user agent assumes that the server
can handle a search on the document. To use the Isindex
element, the server must have a search engine that
supports this element.
2.7.4 Link
Level 1
The Link element indicates a relationship between the
document and some other object. A document may have any
number of Link elements.
The Link element is empty (does not have a closing tag),
but takes the same attributes as the Anchor element.
Typical uses are to indicate authorship, related indexes
and glossaries, older or more recent versions, etc.
Links can indicate a static tree structure in which the
document was authored by pointing to a "parent" and
"next" and "previous" document, for example.
Servers may also allow links to be added by those who do
not have the right to alter the body of a document.
2.7.5 Nextid
Level 0
The Nextid element is a parameter read by and generated
by text editing software to create unique identifiers.
This tag takes a single attribute which is the next
document-wide alpha-numeric identifier to be allocated
of the form z123:
<NEXTID N=Z27>
When modifying a document, existing anchor identifiers
should not be reused, as these identifiers may be
referenced by other documents. Human writers of HTML
usually use mnemonic alphabetical identifiers.
HTML user agents may ignore the Nextid element. Support
for the Nextid element does not impact HTML user agents
Berners-Lee, Connolly, et. al. Page 19
HTML 2.0 February 8, 1995
in any way.
2.7.6 Title
<TITLE> ... </TITLE>
Level 0
Every HTML document must contain a Title element. The
title should identify the contents of the document in a
global context, and may be used in a history lists and
as a label for the window displaying the document.
Unlike headings, titles are not typically rendered in
the text of a document itself.
The Title element must occur within the head of the
document, and may not contain anchors, paragraph tags,
or highlighting. Only one title is allowed in a
document.
NOTE: The length of a title is not limited; however,
long titles may be truncated in some applications. To
minimize this possibility, titles should be fewer than
64 characters. Also keep in mind that a short title,
such as Introduction, may be meaningless out of context.
An example of a meaningful title might be "Introduction
to HTML Elements."
2.7.7 Meta
Level 1
The Meta element is used within the Head element to
embed document meta-information not defined by other
HTML elements. Such information can be extracted by
servers/clients for use in identifying, indexing, and
cataloging specialized document meta-information.
Although it is generally preferable to use named
elements that have well-defined semantics for each type
of meta-information, such as a title, this element is
provided for situations where strict SGML parsing is
necessary and the local DTD is not extensible.
In addition, HTTP servers can read the content of the
document head to generate response headers corresponding
to any elements defining a value for the attribute HTTP-
EQUIV. This provides document authors a mechanism (not
necessarily the preferred one) for identifying
information that should be included in the response
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headers for an HTTP request.
Attributes of the Meta element:
HTTP-EQUIV
This attribute binds the element to an HTTP response
header. If the semantics of the HTTP response header
named by this attribute is known, then the contents can
be processed based on a well-defined syntactic mapping
whether or not the DTD includes anything about it. HTTP
header names are not case sensitive. If not present, the
NAME attribute should be used to identify this meta-
information and it should not be used within an HTTP
response header.
NAME
Meta-information name. If the NAME attribute is not
present, the name can be assumed equal to the value of
HTTP-EQUIV.
CONTENT
The meta-information content to be associated with the
given name and/or HTTP response header.
Examples
If the document contains:
<META HTTP-EQUIV="Expires" CONTENT="Tue, 04 Dec 1993 21:29:02
GMT">
<META HTTP-EQUIV="Keywords" CONTENT="Fred, Barney">
<META HTTP-EQUIV="Reply-
to" content="fielding@ics.uci.edu (Roy Fielding)">
Expires: Tue, 04 Dec 1993 21:29:02 GMT
Keywords: Fred, Barney
Reply-to: fielding@ics.uci.edu (Roy Fielding)
When the HTTP-EQUIV attribute is not present, the server
should not generate an HTTP response header for this
meta-information; e.g.,
<META NAME="IndexType" CONTENT="Service">
Do not use the Meta element to define information that
should be associated with an existing HTML element.
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Example of an inappropriate use of the Meta element:
<META NAME="Title" CONTENT="The Etymology of Dunsel">
Do not name an HTTP-EQUIV equal to a response header
that should typically only be generated by the HTTP
server. Some inappropriate names are "Server", "Date",
and "Last-modified". Whether a name is inappropriate
depends on the particular server implementation. It is
recommended that servers ignore any Meta elements that
specify HTTP-equivalents equal (case-insensitively) to
their own reserved response headers.
2.8 The Body Element and Related Elements
The following elements may be included in the body of an
HTML document:
2.8.1 Body
<BODY> ... </BODY>
Level 0
The Body element identifies the body component of an
HTML document. Specifically, the body of a document may
contain links, text, and formatting information within
<BODY> and </BODY> tags.
2.8.2 Address
<ADDRESS> ... </ADDRESS>
Level 0
The Address element specifies such information as
address, signature and authorship, often at the top or
bottom of a document.
Typically, an Address is rendered in an italic typeface
and may be indented. The Address element implies a
paragraph break before and after.
Example of use:
<ADDRESS>
Newsletter editor<BR>
J.R. Brown<BR>
JimquickPost News, Jumquick, CT 01234<BR>
Tel (123) 456 7890
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</ADDRESS>
2.8.3 Anchor
<A> ... </A>
Level 0
An anchor is a marked text that is the start and/or
destination of a hypertext link. Anchor elements are
defined by the <A> tag. The <A> tag accepts several
attributes, but either the NAME or HREF attribute is
required.
Attributes of the <A> tag:
HREF
Level 0
If the HREF attribute is present, the text between the
opening and closing anchor tags becomes hypertext. If
this hypertext is selected by readers, they are moved to
another document, or to a different location in the
current document, whose network address is defined by
the value of the HREF attribute.
Example:
See <A HREF="http://www.hal.com/">HaL</A>'s information
for more details.
In this example, selecting "HaL" takes the reader to a
document at http://www.hal.com. The format of the
network address is specified in the URI specification
for print readers.
With the HREF attribute, the form HREF="#identifier" can
refer to another anchor in the same document.
Example:
The <A HREF="document.html#glossary">glossary</A>
defines terms used in this document.
In this example, selecting "glossary" takes the reader
to another anchor (i.e., <A
NAME="glossary">Glossary</A>) in the same document
(document.html). The NAME attribute is described below.
If the anchor is in another document, the HREF attribute
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may be relative to the document's address or the
specified base address (see 2.7.2 Base).
NAME
Level 0
If present, the NAME attribute allows the anchor to be
the target of a link. The value of the NAME attribute is
an identifier for the anchor. Identifiers are arbitrary
strings but must be unique within the HTML document.
Example of use:
<A NAME="coffee">Coffee</A> is an example of ...
...
An example of this is <A HREF="#coffee">coffee</A>.
Another document can then make a reference explicitly to
this anchor by putting the identifier after the address,
separated by a hash sign:
<A NAME="drinks.html#coffee">
TITLE
Level 1
The TITLE attribute is informational only. If present,
the TITLE attribute should provide the title of the
document whose address is given by the HREF attribute.
The TITLE attribute is useful for at least two reasons.
The HTML user agent may display the title of the
document prior to retrieving it, for example, as a
margin note or on a small box while the mouse is over
the anchor, or while the document is being loaded.
Another reason is that documents that are not marked up
text, such as graphics, plain text and Gopher menus, do
not have titles. The TITLE attribute can be used to
provide a title to such documents. When using the TITLE
attribute, the title should be valid and unique for the
destination document.
REL
Level 1
The REL attribute gives the relationship(s) described by
the hypertext link from the anchor to the target. The
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value is a comma-separated list of relationship values.
Values and their semantics will be registered by the
HTML registration authority. The default relationship if
none other is given is void. The REL attribute is only
used when the HREF attribute is present.
REV
Level 1
The REV attribute is the same as the REL attribute, but
the semantics of the link type are in the reverse
direction. A link from A to B with REL="X" expresses the
same relationship as a link from B to A with REV="X". An
anchor may have both REL and REV attributes.
URN
Level 1
If present, the URN attribute specifies a uniform
resource name (URN) for a target document. The format of
URNs is under discussion (1994) by various working
groups of the Internet Engineering Task Force.
METHODS
The METHODS attributes of anchors and links provide
information about the functions that the user may
perform on an object. These are more accurately given by
the HTTP protocol when it is used, but it may, for
similar reasons as for the TITLE attribute, be useful to
include the information in advance in the link. For
example, the HTML user agent may chose a different
rendering as a function of the methods allowed; for
example, something that is searchable may get a
different icon.
The value of the METHODS attribute is a comma separated
list of HTTP methods supported by the object for public
use.
See also: 2.7.4 Link
2.8.4 Blockquote
<BLOCKQUOTE> ... </BLOCKQUOTE>
Level 0
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The Blockquote element is used to contain text quoted
from another source.
A typical rendering might be a slight extra left and
right indent, and/or italic font. The Blockquote element
causes a paragraph break, and typically provides space
above and below the quote.
Single-font rendition may reflect the quotation style of
Internet mail by putting a vertical line of graphic
characters, such as the greater than symbol (>), in the
left margin.
Example of use:
I think the poem ends
<BLOCKQUOTE>
<P>Soft you now, the fair Ophelia. Nymph,
in thy orisons, be all my sins remembered.
</BLOCKQUOTE>
but I am not sure.
2.8.5 Headings
<H1> ... </H1> through <H6> ... </H6>
Level 0
HTML defines six levels of heading. A Heading element
implies all the font changes, paragraph breaks before
and after, and white space necessary to render the
heading.
The highest level of headings is H1, followed by H2 ...
H6.
Example of use:
<H1>This is a heading</H1>
Here is some text
<H2>Second level heading</H2>
Here is some more text.
The rendering of headings is determined by the HTML user
agent, but typical renderings are:
<H1> ... </H1>
Bold, very-large font, centered. One or two blank lines
above and below.
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<H2> ... </H2>
Bold, large font, flush-left. One or two blank lines
above and below.
<H3> ... </H3>
Italic, large font, slightly indented from the left
margin. One or two blank lines above and below.
<H4> ... </H4>
Bold, normal font, indented more than H3. One blank line
above and below.
<H5> ... </H5>
Italic, normal font, indented as H4. One blank line
above.
<H6> ... </H6>
Bold, indented same as normal text, more than H5. One
blank line above.
Although heading levels can be skipped (for example,
from H1 to H3), this practice is discouraged as skipping
heading levels may produce unpredictable results when
generating other representations from HTML.
2.9 Overview of Character-Level Elements
Level 2 (all elements)
Character-level elements are used to specify either the
logical meaning or the physical appearance of marked
text without causing a paragraph break. Like most other
elements, character-level elements include both opening
and closing tags. Only the characters between the tags
are affected:
This is <EM>emphasized</EM> text.
Character-level tags may be ignored by minimal HTML
applications.
Character-level tags are interpreted from left to right
as they appear in the flow of text. Level 1 HTML user
agents must render highlighted text distinctly from
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plain text. Additionally, EM content must be rendered as
distinct from STRONG content, and B content must
rendered as distinct from I content.
Character-level elements may be nested within the
content of other character-level elements; however, HTML
user agents are not required to render nested character-
level elements distinctly from non-nested elements:
plain <B>bold <I>italic</I></B>
may the rendered the same as
plain <B>bold </B><I>italic</I>
Note that typical renderings for information type
elements vary between applications. If a specific
rendering is necessary, for example, when referring to a
specific text attribute as in "The italic parts are
mandatory", a formating element can be used to ensure
that the intended rendered is used where possible.
2.10 Information Type Elements
Note that different information type elements may be
rendered in the same way.
2.10.1 Citation
<CITE>...</CITE>
The Citation element specifies a citation; typically
rendered as italics.
2.10.2 Code
<CODE> ... </CODE>
The Code element indicates an example of code; typically
rendered as monospaced . Do not confuse with the
Preformatted Text element.
2.10.3 Emphasis
<EM> ... </EM>
The Emphasis element indicates typographic emphasis,
typically rendered as italics.
2.10.4 Keyboard
<KBD> ... </KBD>
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The Keyboard element indicates text typed by a user;
typically rendered as monospaced . It might commonly be
used in an instruction manual.
2.10.5 Sample
<SAMP> ... </SAMP>
The Sample element indicates a sequence of literal
characters; typically rendered as monospaced.
2.10.6 Strong
<STRONG> ... </STRONG>
The Strong element indicates strong typographic
emphasis, typically rendered in bold.
2.10.7 Variable
<VAR> ... </VAR>
The Variable element indicates a variable name;
typically rendered as italic.
2.11 Character Format Elements
Character format elements are used to specify the format
of marked text. Example of use:
2.11.1 Bold
<B> ... </B>
The Bold element specifies that the text should be
rendered in boldface, where available. Otherwise,
alternative mapping is allowed.
2.11.2 Italic
<I> ... </I>
The Italic element specifies that the text should be
rendered in italic font, where available. Otherwise,
alternative mapping is allowed.
2.11.3 Teletype
<TT> ... </TT>
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The Teletype element specifies that the text should be
rendered in fixed-width typewriter font.
2.12 Image Element
<IMG>
Level 0
The Image element is used to incorporate in-line
graphics (typically icons or small graphics) into an
HTML document. This element cannot be used for embedding
other HTML text.
HTML user agents that cannot render in-line images
ignore the Image element unless it contains the ALT
attribute. Note that some HTML user agents can render
linked graphics but not in-line graphics. If a graphic
is essential, you may want to create a link to it rather
than to put it in-line. If the graphic is not essential,
then the Image element is appropriate.
The Image element, which is empty (no closing tag), has
these attributes:
ALIGN
The ALIGN attribute accepts the values TOP or MIDDLE or
BOTTOM, which specifies if the following line of text is
aligned with the top, middle, or bottom of the graphic.
ALT
Optional text as an alternative to the graphic for
rendering in non-graphical environments. Alternate text
should be provided whenever the graphic is not rendered.
Alternate text is mandatory for Level 0 documents.
Example of use:
<IMG SRC="triangle.gif" ALT="Warning:"> Be sure to read
these instructions.
ISMAP
The ISMAP (is map) attribute identifies an image as an
image map. Image maps are graphics in which certain
regions are mapped to URLs. By clicking on different
regions, different resources can be accessed from the
same graphic. Example of use:
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<A HREF="http://machine/htbin/imagemap/sample">
<IMG SRC="sample.gif" ISMAP>
</A>
SRC
The value of the SRC attribute is the URL of the
document to be embedded; only images can be embedded,
not HTML text. Its syntax is the same as that of the
HREF attribute of the <A> tag. SRC is mandatory. Image
elements are allowed within anchors.
Example of use:
<IMG SRC ="triangle.gif">Be sure to read these
instructions.
2.13 List Elements
HTML supports several types of lists, all of which may
be nested.
2.13.1 Definition List
<DL> ... </DL>
Level 0
A definition list is a list of terms and corresponding
definitions. Definition lists are typically formatted
with the term flush-left and the definition, formatted
paragraph style, indented after the term.
Example of use:
<DL>
<DT>Term<DD>This is the definition of the first term.
<DT>Term<DD>This is the definition of the second term.
</DL>
If the DT term does not fit in the DT column (one third
of the display area), it may be extended across the page
with the DD section moved to the next line, or it may be
wrapped onto successive lines of the left hand column.
Single occurrences of a <DT> tag without a subsequent
<DD> tag are allowed, and have the same significance as
if the <DD> tag had been present with no text.
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The opening list tag must be <DL> and must be
immediately followed by the first term (<DT>).
The definition list type can take the COMPACT attribute,
which suggests that a compact rendering be used, because
the list items are small and/or the entire list is
large.
Unless you provide the COMPACT attribute, the HTML user
agent may leave white space between successive DT, DD
pairs.The COMPACT attribute may also reduce the width of
the left-hand (DT) column.
If using the COMPACT attribute, the opening list tag
must be <DL COMPACT>, which must be immediately followed
by the first <DT> tag:
<DL COMPACT>
<DT>Term<DD>This is the first definition in compact format.
<DT>Term<DD>This is the second definition in compact format.
</DL>
2.13.2 Directory List
<DIR> ... </DIR>
Level 0
A Directory List element is used to present a list of
items containing up to 20 characters each. Items in a
directory list may be arranged in columns, typically 24
characters wide. If the HTML user agent can optimize the
column width as function of the widths of individual
elements, so much the better.
A directory list must begin with the <DIR> tag which is
immediately followed by a <LI> (list item) tag:
<DIR>
<LI>A-H<LI>I-M
<LI>M-R<LI>S-Z
</DIR>
2.13.3 Menu List
<MENU> ... </MENU>
Level 0
A menu list is a list of items with typically one line
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per item. The menu list style is more compact than the
style of an unordered list.
A menu list must begin with a <MENU> tag which is
immediately followed by a <LI> (list item) tag:
<MENU>
<LI>First item in the list.
<LI>Second item in the list.
<LI>Third item in the list.
</MENU>
2.13.4 Ordered List
<OL> ... </OL>
Level 0
The Ordered List element is used to present a numbered
list of items, sorted by sequence or order of
importance.
An ordered list must begin with the <OL> tag which is
immediately followed by a <LI> (list item) tag:
<OL>
<LI>Click the Web button to open the Open the URL window.
<LI>Enter the URL number in the text field of the Open URL
window. The Web document you specified is displayed.
<LI>Click highlighted text to move from one link to another.
</OL>
The Ordered List element can take the COMPACT attribute,
which suggests that a compact rendering be used.
2.13.5 Unordered List
<UL> ... </UL>
Level 0
The Unordered List element is used to present a list of
items which is typically separated by white space and/or
marked by bullets.
An unordered list must begin with the <UL> tag which is
immediately followed by a <LI> (list item) tag:
<UL>
<LI>First list item
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<LI>Second list item
<LI>Third list item
</UL>
2.14 Other Elements
2.14.1 Paragraph
<P>
Level 0
The Paragraph element indicates a paragraph. The exact
indentation, leading, etc. of a paragraph is not defined
and may be a function of other tags, style sheets, etc.
Typically, paragraphs are surrounded by a vertical space
of one line or half a line. This is typically not the
case within the Address element and or is never the case
within the Preformatted Text element. With some HTML
user agents, the first line in a paragraph is indented.
Example of use:
<H1>This Heading Precedes the Paragraph</H1>
<P>This is the text of the first paragraph.
<P>This is the text of the second paragraph. Although you
do not need to start paragraphs on new lines, maintaining
this convention facilitates document maintenance.
<P>This is the text of a third paragraph.
2.14.2 Preformatted Text
<PRE> ... </PRE>
Level 0
The Preformatted Text element presents blocks of text in
fixed-width font, and so is suitable for text that has
been formatted on screen.
The <PRE> tag may be used with the optional WIDTH
attribute, which is a Level 1 feature. The WIDTH
attribute specifies the maximum number of characters for
a line and allows the HTML user agent to select a
suitable font and indentation. If the WIDTH attribute is
not present, a width of 80 characters is assumed. Where
the WIDTH attribute is supported, widths of 40, 80 and
132 characters should be presented optimally, with other
widths being rounded up.
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Within preformatted text:
- Line breaks within the text are rendered as a move
to the beginning of the next line.
- The <P> tag should not be used. If found, it should
be rendered as a move to the beginning of the next line.
- Anchor elements and character highlighting elements
may be used.
- Elements that define paragraph formatting
(headings, address, etc.) must not be used.
- The horizontal tab character (encoded in US-ASCII
and ISO-8859-1 as decimal 9) must be
interpreted as the smallest positive nonzero number of
spaces which will leave the number of characters so far
on the line as a multiple of 8. Its use is not
recommended however.
NOTE: References to the "beginning of a new line" do not
imply that the renderer is forbidden from using a
constant left indent for rendering preformatted text.
The left indent may be constrained by the width
required.
Example of use:
<PRE WIDTH="80">
This is an example line.
</PRE>
NOTE: Within a Preformatted Text element, the constraint
that the rendering must be on a fixed horizontal
character pitch may limit or prevent the ability of the
HTML user agent to render highlighting elements
specially.
2.14.3 Line Break
<BR>
Level 0
The Line Break element specifies that a new line must be
started at the given point. A new line indents the same
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as that of line-wrapped text.
Example of use:
<P>
Pease porridge hot<BR>
Pease porridge cold<BR>
Pease porridge in the pot<BR>
Nine days old.
2.14.4 Horizontal Rule
<HR>
Level 0
A Horizontal Rule element is a divider between sections
of text such as a full width horizontal rule or
equivalent graphic.
Example of use:
<HR>
<ADDRESS>February 8, 1995, CERN</ADDRESS>
</BODY>
2.15 Form Elements
Forms are created by placing input fields within
paragraphs, preformatted/literal text, and lists. This
gives considerable flexibility in designing the layout
of forms.
The following elements (all are HTML 2 features) are
used to create forms:
FORM
A form within a document.
INPUT
One input field.
OPTION
One option within a Select element.
SELECT
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A selection from a finite set of options.
TEXTAREA
A multi-line input field.
Each variable field is defined by an Input, Textarea, or
Option element and must have an NAME attribute to
identify its value in the data returned when the form is
submitted.
Example of use (a questionnaire form):
<H1>Sample Questionnaire</H1>
<P>Please fill out this questionnaire:
<FORM METHOD="POST" ACTION="http://www.hal.com/sample">
<P>Your name: <INPUT NAME="name" size="48">
<P>Male <INPUT NAME="gender" TYPE=RADIO VALUE="male">
<P>Female <INPUT NAME="gender" TYPE=RADIO VALUE="female">
<P>Number in family: <INPUT NAME="family" TYPE=text>
<P>Cities in which you maintain a residence:
<UL>
<LI>Kent <INPUT NAME="city" TYPE=checkbox VALUE="kent">
<LI>Miami <INPUT NAME="city" TYPE=checkbox VALUE="miami">
<LI>Other <TEXTAREA NAME="other" cols=48 rows=4></textarea>
</UL>
Nickname: <INPUT NAME="nickname" SIZE="42">
<P>Thank you for responding to this questionnaire.
<P><INPUT TYPE=SUBMIT> <INPUT TYPE=RESET>
</FORM>
In the example above, the <P> and <UL> tags have been
used to lay out the text and input fields. The HTML user
agent is responsible for handling which field will
currently get keyboard input.
Many platforms have existing conventions for forms, for
example, using Tab and Shift keys to move the keyboard
focus forwards and backwards between fields, and using
the Enter key to submit the form. In the example, the
SUBMIT and RESET buttons are specified explicitly with
special purpose fields. The SUBMIT button is used to e-
mail the form or send its contents to the server as
specified by the ACTION attribute, while RESET resets
the fields to their initial values. When the form
consists of a single text field, it may be appropriate
to leave such buttons out and rely on the Enter key.
The Input element is used for a large variety of types
of input fields.
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To let users enter more than one line of text, use the
Textarea element.
2.15.1 Representing Choices
The radio button and checkbox types of input field can
be used to specify multiple choice forms in which every
alternative is visible as part of the form. An
alternative is to use the Select element which is
typically rendered in a more compact fashion as a pull
down combo list.
2.15.2 Form
<FORM> ... </FORM>
Level 2
The Form element is used to delimit a data input form.
There can be several forms in a single document, but the
Form element can't be nested.
The ACTION attribute is a URL specifying the location to
which the contents of the form is submitted to elicit a
response. If the ACTION attribute is missing, the URL of
the document itself is assumed. The way data is
submitted varies with the access protocol of the URL,
and with the values of the METHOD and ENCTYPE
attributes.
In general:
- the METHOD attribute selects variations in the
protocol.
- the ENCTYPE attribute specifies the format of the
submitted data in case the protocol does not impose a
format itself.
The Level 2 specification defines and requires support
for the HTTP access protocol only.
When the ACTION attribute is set to an HTTP URL, the
METHOD attribute must be set to an HTTP method as
defined by the HTTP method specification in the IETF
draft HTTP standard. The default METHOD is GET, although
for many applications, the POST method may be preferred.
With the post method, the ENCTYPE attribute is a MIME
type specifying the format of the posted data; by
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default, is application/x-www-form-urlencoded.
Under any protocol, the submitted contents of the form
logically consist of name/value pairs. The names are
usually equal to the NAME attributes of the various
interactive elements in the form.
NOTE: The names are not guaranteed to be unique keys,
nor are the names of form elements required to be
distinct. The values encode the user's input to the
corresponding interactive elements. Elements capable of
displaying a textual or numerical value will return a
name/value pair even when they receive no explicit user
input.
2.15.3 Input
<INPUT>
Level 2
The Input element represents a field whose contents may
be edited by the user.
Attributes of the Input element:
ALIGN
Vertical alignment of the image. For use only with
TYPE=IMAGE in HTML level 2. The possible values are
exactly the same as for the ALIGN attribute of the image
element.
CHECKED
Indicates that a checkbox or radio button is selected.
Unselected checkboxes and radio buttons do not return
name/value pairs when the form is submitted.
MAXLENGTH
Indicates the maximum number of characters that can be
entered into a text field. This can be greater than
specified by the SIZE attribute, in which case the field
will scroll appropriately. The default number of
characters is unlimited.
NAME
Symbolic name used when transferring the form's
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contents. The NAME attribute is required for most input
types and is normally used to provide a unique
identifier for a field, or for a logically related group
of fields.
SIZE
Specifies the size or precision of the field according
to its type. For example, to specify a field with a
visible width of 24 characters:
INPUT TYPE=text SIZE="24"
SRC
A URL or URN specifying an image. For use only with
TYPE=IMAGE in HTML Level 2.
TYPE
Defines the type of data the field accepts. Defaults to
free text. Several types of fields can be defined with
the type attribute:
CHECKBOX
Used for simple Boolean attributes, or for attributes
that can take multiple values at the same time. The
latter is represented by a number of checkbox fields
each of which has the same name. Each selected checkbox
generates a separate name/value pair in the submitted
data, even if this results in duplicate names. The
default value for checkboxes is "on".
HIDDEN
No field is presented to the user, but the content of
the field is sent with the submitted form. This value
may be used to transmit state information about
client/server interaction.
IMAGE
An image field upon which you can click with a pointing
device, causing the form to be immediately submitted.
The coordinates of the selected point are measured in
pixel units from the upper-left corner of the image, and
are returned (along with the other contents of the form)
in two name/value pairs. The x-coordinate is submitted
under the name of the field with .x appended, and the y-
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HTML 2.0 February 8, 1995
coordinate is submitted under the name of the field with
.y appended. Any VALUE attribute is ignored. The image
itself is specified by the SRC attribute, exactly as for
the Image element.
NOTE: In a future version of the HTML specification, the
IMAGE functionality may be folded into an enhanced
SUBMIT field.
PASSWORD is the same as the TEXT attribute, except that
text is not displayed as it is entered.
RADIO is used for attributes that accept a single value
from a set of alternatives. Each radio button field in
the group should be given the same name. Only the
selected radio button in the group generates a
name/value pair in the submitted data. Radio buttons
require an explicit VALUE attribute.
RESET is a button that when pressed resets the form's
fields to their specified initial values. The label to
be displayed on the button may be specified just as for
the SUBMIT button.
SUBMIT is a button that when pressed submits the form.
You can use the VALUE attribute to provide a non-
editable label to be displayed on the button. The
default label is application-specific. If a SUBMIT
button is pressed in order to submit the form, and that
button has a NAME attribute specified, then that button
contributes a name/value pair to the submitted data.
Otherwise, a SUBMIT button makes no contribution to the
submitted data.
TEXT is used for a single line text entry fields. Use in
conjunction with the SIZE and MAXLENGTH attributes. Use
the Textarea element for text fields which can accept
multiple lines.
VALUE
The initial displayed value of the field, if it displays
a textual or numerical value; or the value to be
returned when the field is selected, if it displays a
Boolean value. This attribute is required for radio
buttons.
2.15.4 Option
<OPTION>
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HTML 2.0 February 8, 1995
Level 2
The Option element can only occur within a Select
element. It represents one choice, and can take these
attributes:
DISABLED
Proposed.
SELECTED
Indicates that this option is initially selected.
VALUE
When present indicates the value to be returned if this
option is chosen. The returned value defaults to the
contents of the Option element.
The contents of the Option element is presented to the
user to represent the option. It is used as a returned
value if the VALUE attribute is not present.
2.15.5 Select
<SELECT NAME=... > ... </SELECT>
Level 2
The Select element allows the user to chose one of a set
of alternatives described by textual labels. Every
alternative is represented by the Option element.
Attributes are:
ERROR
Proposed.
MULTIPLE
The MULTIPLE attribute is needed when users are allowed
to make several selections, e.g. <SELECT MULTIPLE>.
NAME
Specifies the name that will submitted as a name/value
pair.
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SIZE
Specifies the number of visible items. If this is
greater than one, then the resulting form control will
be a list.
The Select element is typically rendered as a pull down
or pop-up list. For example:
<SELECT NAME="flavor">
<OPTION>Vanilla
<OPTION>Strawberry
<OPTION>Rum and Raisin
<OPTION>Peach and Orange
</SELECT>
If no option is initially marked as selected, then the
first item listed is selected.
2.15.6 Text Area
<TEXTAREA> ... </TEXTAREA>
Level 2
The Textarea element lets users enter more than one line
of text. For example:
<TEXTAREA NAME="address" ROWS=64 COLS=6>
HaL Computer Systems
1315 Dell Avenue
Campbell, California 95008
</TEXTAREA>
The text up to the end tag (</TEXTAREA>) is used to
initialize the field's value. This end tag is always
required even if the field is initially blank. When
submitting a form, lines in a TEXTAREA should be
terminated using CR/LF.
In a typical rendering, the ROWS and COLS attributes
determine the visible dimension of the field in
characters. The field is rendered in a fixed-width font.
HTML user agents should allow text to extend beyond
these limits by scrolling as needed.
NOTE: In the initial design for forms, multi-line text
fields were supported by the Input element with
TYPE=TEXT. Unfortunately, this causes problems for
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HTML 2.0 February 8, 1995
fields with long text values. SGML's default (Reference
Quantity Set) limits the length of attribute literals to
only 240 characters. The HTML 2.0 SGML declaration
increases the limit to 1024 characters.
2.16 Character Data
Level 0
The characters between HTML tags represent text. A HTML document
(including tags and text) is encoded using the coded character
set specified by the "charset" parameter of the "text/html"
media type. For levels defined in this specification, the
"charset" parameter is restricted to "US-ASCII" or "ISO-8859-1".
ISO-8859-1 encodes a set of characters known as Latin Alphabet
No. 1, or simply Latin-1. Latin-1 includes characters from most
Western European languages, as well as a number of control
characters. Latin-1 also includes a non-breaking space, a soft
hyphen indicator, 93 graphical characters, 8 unassigned
characters, and 25 control characters.
Because non-breaking space and soft hyphen indicator are
not recognized and interpreted by all HTML user agents,
their use is discouraged.
There are 58 character positions occupied by control
characters. See Section 2.16.2 for details on the
interpretation of control characters.
Because certain special characters are subject to
interpretation and special processing, information
providers and HTML user agent implementors should follow
the guidelines in Section 2.16.1.
In addition, HTML provides
character entity references (see Section 2.17.2) and
numerical character references (see Section 2.17.3) to
facilitate the entry and interpretation of characters by
name and by numerical position.
Because certain characters will be interpreted as
markup, they must be represented by entity references as described
in Section 2.16.3 and Section 2.16.4.
2.16.1 Special Characters
Certain characters have special meaning in HTML
documents. There are two printing characters which may
be interpreted by an HTML application to have an effect
of the format of the text:
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HTML 2.0 February 8, 1995
Space
- Interpreted as a word space (place where a line can
be broken) in all contexts except the Preformatted Text
element.
- Interpreted as a nonbreaking space within the
Preformatted Text element.
Hyphen
- Interpreted as a hyphen glyph in all contexts
- Interpreted as a potential word space by
hyphenation engine
2.16.2 Control Characters
Control characters are non-printable characters that are
typically used for communication and device control, as
format effectors, and as information separators.
In SGML applications, the use of control characters is
limited in order to maximize the chance of successful
interchange over heterogenous networks and operating
systems. In HTML, only three control characters are
used: Horizontal Tab (HT, encoded as 9 decimal
in US-ASCII and ISO-8859-1), Carriage Return, and
Line Feed.
Horizontal Tab is interpreted as a word space in all contexts
except preformatted text. Within preformatted text, the tab
should be interpreted to shift the horizontal column position
to the next position which is a multiple of 8 on the same
line; that is, col := (col+8) mod 8.
Carriage Return and Line Feed are conventionally used
to represent end of line. For Internet Media Types defined as
"text/*", the sequence CR LF is used to represent an end of
line. In practice, text/html documents are frequently
represented and transmitted using an end of line convention
that depends on the conventions of the source of the
document; frequently, that representation consists of CR
only, LF only, or CR LF combination. In HTML, end of line in
any of its variations is interpreted as a word space in all
contexts except preformatted text. Within preformatted text,
HTML interpreting agents should expect to treat any of the
three common representations of end-of-line as starting
a new line.
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2.16.3 Numeric Character References
In addition to any mechanism by which characters may be
represented by the encoding of the HTML document, it is
possible to explicitly reference the printing characters of
the ISO-8859-1 character encoding using a numeric character
reference. See Section
2.17.1 for a list of the characters, their names and
input syntax.
Two reasons for using a numeric character reference:
- the keyboard does not provide a key for the
character, such as on U.S. keyboards which do not
provide European characters
- the character may be interpreted as SGML coding,
such as the ampersand (&), double quotes ("), the lesser
(<) and greater (>) characters
Numeric character references are represented in an HTML
document as SGML entities whose name is number sign (#)
followed by a numeral from 32-126 and 161-255. The HTML
DTD includes a numeric character for each of the
printing characters of the ISO-8859-1 encoding, so that one
may reference them by number if it is inconvenient to enter
them directly:
the ampersand (&), double quotes ("),
lesser (<) and greater (>) characters
2.16.4 Character Entities
In addition, many of the Latin alphabet No. 1 set of printing
characters may be represented within the text of an HTML
document by a character entity. See 2.17.2 for a list of
the characters, names, input syntax, and descriptions.
See 5.2.1 for the SGML entity definitions of "Added
Latin 1 for HTML".
Two reasons for using a character entity:
- the keyboard does not provide a key for the
character, such as on U.S. keyboards which do not
provide European characters
- the character may be interpreted as SGML coding,
such as the ampersand (&), double quotes ("), the lesser
(<) and greater (>) characters
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HTML 2.0 February 8, 1995
A character entity is represented in an HTML document as
an SGML entity whose name is defined in the HTML DTD.
The HTML DTD includes a character entity for each of the
SGML markup characters and for each of the printing
characters in the upper half of Latin-1, so that one may
reference them by name if it is inconvenient to enter
them directly:
the ampersand (&), double quotes ("),
lesser (<) and greater (>) characters
Kurt Gödel was a famous logician and mathematician.
NOTE: To ensure that a string of characters is not
interpreted as markup, represent all occurrences of <,
>, and & by character or entity references.
NOTE: There are SGML features, CDATA and RCDATA, to
allow most <, >, and & characters to be entered without
the use of entity or character references. Because these
features tend to be used and implemented inconsistently,
and because they require 8-bit characters to represent
non-ASCII characters, they are not used in this version
of the HTML DTD. An earlier HTML specification included
an Example element (<XMP>) whose syntax is not
expressible in SGML. No markup was recognized inside of
the Example element except the </XMP> end tag. While
HTML user agents are encouraged to support this idiom,
its use is deprecated.
2.17 Character Entity Sets
The following entity names are used in HTML, always
prefixed by ampersand (&) and followed by a semicolon as
shown.
They represent particular graphic characters which have
special meanings in places in the markup, or may not be
part of the character set available to the writer.
2.17.1 Numeric and Special Graphic Entities
The following table lists each of the supported
characters specified in the Numeric and Special Graphic
entity set, along with its name, syntax for use, and
description. This list is derived from ISO Standard
8879:1986//ENTITIES Numeric and Special Graphic//EN
however HTML does not provide support for the entire
entity set. Only the entities listed below are
Berners-Lee, Connolly, et. al. Page 47
HTML 2.0 February 8, 1995
supported.
GLYPH NAME SYNTAX DESCRIPTION
< lt < Less than sign
> gt > Greater than sign
& amp & Ampersand
" quot " Double quote sign
2.17.2 ISO Latin 1 Character Entities
The following table lists each of the characters
specified in the Added Latin 1 entity set, along with
its name, syntax for use, and description. This list is
derived from ISO Standard 8879:1986//ENTITIES Added
Latin 1//EN. HTML supports the entire entity set.
NAME SYNTAX DESCRIPTION
Aacute Á Capital A, acute accent
Agrave À Capital A, grave accent
Acirc  Capital A, circumflex accent
Atilde à Capital A, tilde
Aring Å Capital A, ring
Auml Ä Capital A, dieresis or umlaut mark
AElig Æ Capital AE dipthong (ligature)
Ccedil Ç Capital C, cedilla
Eacute É Capital E, acute accent
Egrave È Capital E, grave accent
Ecirc Ê Capital E, circumflex accent
Euml Ë Capital E, dieresis or umlaut mark
Iacute Í Capital I, acute accent
Igrave Ì Capital I, grave accent
Icirc Î Capital I, circumflex accent
Iuml Ï Capital I, dieresis or umlaut mark
ETH Ð Capital Eth, Icelandic
Ntilde Ñ Capital N, tilde
Oacute Ó Capital O, acute accent
Ograve Ò Capital O, grave accent
Ocirc Ô Capital O, circumflex accent
Otilde Õ Capital O, tilde
Ouml Ö Capital O, dieresis or umlaut mark
Oslash Ø Capital O, slash
Uacute Ú Capital U, acute accent
Ugrave Ù Capital U, grave accent
Ucirc Û Capital U, circumflex accent
Uuml Ü Capital U, dieresis or umlaut mark
Yacute Ý Capital Y, acute accent
THORN Þ Capital THORN, Icelandic
szlig ß Small sharp s, German (sz ligature)
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aacute á Small a, acute accent
agrave à Small a, grave accent
acirc â Small a, circumflex accent
atilde ã Small a, tilde
aring å Small a, ring
auml ä Small a, dieresis or umlaut mark
aelig æ Small ae dipthong (ligature)
ccedil ç Small c, cedilla
eacute é Small e, acute accent
egrave è Small e, grave accent
ecirc ê Small e, circumflex accent
euml ë Small e, dieresis or umlaut mark
iacute í Small i, acute accent
igrave ì Small i, grave accent
icirc î Small i, circumflex accent
iuml ï Small i, dieresis or umlaut mark
eth ð Small eth, Icelandic
ntilde ñ Small n, tilde
oacute ó Small o, acute accent
ograve ò Small o, grave accent
ocirc ô Small o, circumflex accent
otilde õ Small o, tilde
ouml ö Small o, dieresis or umlaut mark
oslash ø Small o, slash
uacute ú Small u, acute accent
ugrave ù Small u, grave accent
ucirc û Small u, circumflex accent
uuml ü Small u, dieresis or umlaut mark
yacute ý Small y, acute accent
thorn þ Small thorn, Icelandic
yuml ÿ Small y, dieresis or umlaut mark
2.17.3 Numerical Character References
This list, sorted numerically, is derived from ISO-8859-1
8-bit single-byte coded graphic character set:
REFERENCE DESCRIPTION
� - Unused
Horizontal tab
Line feed
- Unused
Space
! Exclamation mark
" Quotation mark
# Number sign
$ Dollar sign
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HTML 2.0 February 8, 1995
% Percent sign
& Ampersand
' Apostrophe
( Left parenthesis
) Right parenthesis
* Asterisk
+ Plus sign
, Comma
- Hyphen
. Period (fullstop)
/ Solidus (slash)
0 - 9 Digits 0-9
: Colon
; Semi-colon
< Less than
= Equals aign
> Greater than
? Question mark
@ Commercial at
A - Z Letters A-Z
[ Left square bracket
\ Reverse solidus (backslash)
] Right square bracket
^ Caret
_ Horizontal bar
` Acute accent
a - z Letters a-z
{ Left curly brace
| Vertical bar
} Right curly brace
~ Tilde
- Unused
¡ Inverted exclamation
¢ Cent sign
£ Pound sterling
¤ General currency sign
¥ Yen sign
¦ Broken vertical bar
§ Section sign
¨ Umlaut (dieresis)
© Copyright
ª Feminine ordinal
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« Left angle quote, guillemotleft
¬ Not sign
Soft hyphen
® Registered trademark
¯ Macron accent
° Degree sign
± Plus or minus
² Superscript two
³ Superscript three
´ Acute accent
µ Micro sign
¶ Paragraph sign
· Middle dot
¸ Cedilla
¹ Superscript one
º Masculine ordinal
» Right angle quote, guillemotright
¼ Fraction one-fourth
½ Fraction one-half
¾ Fraction three-fourths
¿ Inverted question mark
À Capital A, acute accent
Á Capital A, grave accent
 Capital A, circumflex accent
à Capital A, tilde
Ä Capital A, ring
Å Capital A, dieresis or umlaut mark
Æ Capital AE dipthong (ligature)
Ç Capital C, cedilla
È Capital E, acute accent
É Capital E, grave accent
Ê Capital E, circumflex accent
Ë Capital E, dieresis or umlaut mark
Ì Capital I, acute accent
Í Capital I, grave accent
Î Capital I, circumflex accent
Ï Capital I, dieresis or umlaut mark
Ð Capital Eth, Icelandic
Ñ Capital N, tilde
Ò Capital O, acute accent
Ó Capital O, grave accent
Ô Capital O, circumflex accent
Õ Capital O, tilde
Ö Capital O, dieresis or umlaut mark
× Multiply sign
Ø Capital O, slash
Ù Capital U, acute accent
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Ú Capital U, grave accent
Û Capital U, circumflex accent
Ü Capital U, dieresis or umlaut mark
Ý Capital Y, acute accent
Þ Capital THORN, Icelandic
ß Small sharp s, German (sz ligature)
à Small a, acute accent
á Small a, grave accent
â Small a, circumflex accent
ã Small a, tilde
ä Small a, dieresis or umlaut mark
å Small a, ring
æ Small ae dipthong (ligature)
ç Small c, cedilla
è Small e, acute accent
é Small e, grave accent
ê Small e, circumflex accent
ë Small e, dieresis or umlaut mark
ì Small i, acute accent
í Small i, grave accent
î Small i, circumflex accent
ï Small i, dieresis or umlaut mark
ð Small eth, Icelandic
ñ Small n, tilde
ò Small o, acute accent
ó Small o, grave accent
ô Small o, circumflex accent
õ Small o, tilde
ö Small o, dieresis or umlaut mark
÷ Division sign
ø Small o, slash
ù Small u, acute accent
ú Small u, grave accent
û Small u, circumflex accent
ü Small u, dieresis or umlaut mark
ý Small y, acute accent
þ Small thorn, Icelandic
ÿ Small y, dieresis or umlaut mark
3. Security Considerations
Anchors, embedded images, and all other elements which
contain URIs as parameters may cause the URI to be
dereferenced in response to user input. In this case,
the security considerations of the URI specification
apply.
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HTML 2.0 February 8, 1995
Documents may be constructed whose visible contents
mislead the reader to follow a link to unsuitable or
offensive material.
4. Obsolete and Proposed Features
4.1 Obsolete Features
This section describes elements that are no longer part
of HTML. Client implementors should implement these
obsolete elements for compatibility with previous
versions of the HTML specification.
4.1.1 Comment
The Comment element is used to delimit unneeded text and
comments. The Comment element has been introduced in
some HTML applications but should be replaced by the
SGML comment feature in new HTML user agents (see
Section 2.6.5).
4.1.2 Highlighted Phrase
The Highlighted Phrase element (<HP>) should be ignored
if not implemented. This element has been replaced by
more meaningful elements (see Section 2.9).
Example of use:
<HP1>first highlighted phrase</HP1>non
highlighted text<HP2>second highlighted
phrase</HP2> etc.
4.1.3 Plain Text
<PLAINTEXT>
The Plain Text element is used to terminates the HTML
entity and to indicate that what follows is not SGML
which does not require parsing. Instead, an old HTTP
convention specified that what followed was an ASCII
(MIME "text/plain") body. Its presence is an
optimization. There is no closing tag.
Example of use:
<PLAINTEXT>
0001 This is line one of a long listing
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HTML 2.0 February 8, 1995
0002 file from <ANY@HOST.INC.COM> which is sent
4.1.4 Example and Listing
<XMP> ... </XMP> and <LISTING> ... </LISTING>
The Example element and Listing element have been
replaced by the Preformatted Text element.
These styles allow text of fixed-width characters to be
embedded absolutely as is into the document. The syntax
is:
<LISTING>
...
</LISTING>
or
<XMP>
...
</XMP>
The text between these tags is typically rendered in a
monospaced font so that any formatting done by character
spacing on successive lines will be maintained.
Between the opening and closing tags:
- The text may contain any ISO Latin-1 printable
characters, expect for the end tag opener. The Example
and Listing elements have historically used
specifications which do not conform to SGML.
Specifically, the text may contain ISO Latin printable
characters, including the tag opener, as long it they
does not contain the closing tag in full.
- SGML does not support this form. HTML user agents
may vary on how they interpret other tags within Example
and Listing elements.
- Line boundaries within the text are rendered as a
move to the beginning of the next line, except for one
immediately following a start tag or immediately
preceding an end tag.
- The horizontal tab character must be
interpreted as the smallest positive nonzero number of
spaces which will leave the number of characters so far
on the line as a multiple of 8. Its use is not
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HTML 2.0 February 8, 1995
recommended.
The Listing element is rendered so that at least 132
characters fit on a line. The Example element is
rendered to that at least 80 characters fit on a line
but is otherwise identical to the Listing element.
4.2 Proposed Features
This section describes proposed HTML elements and
entities that are not currently supported under HTML
Levels 0, 1, or 2, but may be supported in the future.
4.2.1 Defining Instance
<DFN> ... </DFN>
The Defining Instance element indicates the defining
instance of a term. The typical rendering is bold or
bold italic. This element is not widely supported.
4.2.2 Special Characters
To indicate special characters, HTML uses entity or
numeric representations. Additional character
presentations are proposed:
CHARACTER REPRESENTATION
Non-breaking space
Soft-hyphen
Registered ®
Copyright ©
4.2.3 Strike
<STRIKE> ... </STRIKE>
The Strike element is proposed to indicate
strikethrough, a font style in which a horizontal line
appears through characters. This element is not widely
supported.
4.2.4 Underline
<U> ... </U>
The Underline element is proposed to indicate that the
text should be rendered as underlined. This proposed tag
is not supported by all HTML user agents.
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Example of use:
The text <U>shown here</U> is rendered in the document
as underlined.
5. HTML Document Type Definitions
5.1 SGML Declaration for HTML
This is the SGML Declaration for HyperText Markup Language
(HTML) as used by the World Wide Web (WWW) application:
<!SGML "ISO 8879:1986"
--
SGML Declaration for HyperText Markup Language (HTML).
--
CHARSET
BASESET "ISO 646:1983//CHARSET
International Reference Version
(IRV)//ESC 2/5 4/0"
DESCSET 0 9 UNUSED
9 2 9
11 2 UNUSED
13 1 13
14 18 UNUSED
32 95 32
127 1 UNUSED
BASESET "ISO Registration Number 100//CHARSET
ECMA-94 Right Part of
Latin Alphabet Nr. 1//ESC 2/13 4/1"
DESCSET 128 32 UNUSED
160 96 32
CAPACITY SGMLREF
TOTALCAP 150000
GRPCAP 150000
SCOPE DOCUMENT
SYNTAX
SHUNCHAR CONTROLS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 127
BASESET "ISO 646:1983//CHARSET
International Reference Version
(IRV)//ESC 2/5 4/0"
DESCSET 0 128 0
FUNCTION
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HTML 2.0 February 8, 1995
RE 13
RS 10
SPACE 32
TAB SEPCHAR 9
NAMING LCNMSTRT ""
UCNMSTRT ""
LCNMCHAR ".-"
UCNMCHAR ".-"
NAMECASE GENERAL YES
ENTITY NO
DELIM GENERAL SGMLREF
SHORTREF SGMLREF
NAMES SGMLREF
QUANTITY SGMLREF
ATTSPLEN 2100
LITLEN 1024
NAMELEN 72 -- somewhat arbitrary; taken from
internet line length conventions --
PILEN 1024
TAGLEN 2100
FEATURES
MINIMIZE
DATATAG NO
OMITTAG YES
RANK NO
SHORTTAG YES
LINK
SIMPLE NO
IMPLICIT NO
EXPLICIT NO
OTHER
CONCUR NO
SUBDOC NO
FORMAL YES
APPINFO "SDA" -- conforming SGML Document Access application
--
>
<!--
$Id: html.decl,v 1.13 1995/02/08 08:29:33 connolly Exp $
Author: Daniel W. Connolly <connolly@hal.com>
See also: http://www.hal.com/%7Econnolly/html-spec
http://info.cern.ch/hypertext/WWW/MarkUp/MarkUp.html
-->
5.1.1 Sample SGML Open Style Entity Catalog for HTML
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HTML 2.0 February 8, 1995
The SGML standard describes an "entity manager" as the
portion or component of an SGML system that maps SGML
entities into the actual storage model (e.g., the file
system). The standard itself does not define a particular
mapping methodology or notation.
To assist the interoperability among various SGML tools and
systems, the SGML Open consortium has passed a technical
resolution that defines a format for an
application-independent entity catalog that maps external
identifiers and/or entity names to file names.
Each entry in the catalog associates a storage object
identifier (such as a file name) with information about the
external entity that appears in the SGML document. In
addition to entries that associate public identifiers, a
catalog entry can associate an entity name with a storage
object indentifier. For example, the following are
possible catalog entries:
PUBLIC "ISO 8879:1986//ENTITIES Added Latin 1//EN" "iso-lat1.gml"
PUBLIC "-//ACME DTD Writers//DTD General Report//EN" report.dtd
ENTITY "graph1" "graphics\graph1.cgm"
In particular, the following shows entries relevant to HTML.
-- catalog: SGML Open style entity catalog for HTML --
-- $Id: catalog,v 1.1 1994/10/07 21:35:07 connolly Exp $ --
-- Ways to refer to Level 2: most general to most specific --
PUBLIC "-//IETF//DTD HTML//EN" html.dtd
PUBLIC "-//IETF//DTD HTML//EN//2.0" html.dtd
PUBLIC "-//IETF//DTD HTML Level 2//EN" html.dtd
PUBLIC "-//IETF//DTD HTML Level 2//EN//2.0" html.dtd
-- Ways to refer to Level 1: most general to most specific --
PUBLIC "-//IETF//DTD HTML Level 1//EN" html-1.dtd
PUBLIC "-//IETF//DTD HTML Level 1//EN//2.0" html-1.dtd
-- Ways to refer to Level 0: most general to most specific --
PUBLIC "-//IETF//DTD HTML Level 0//EN" html-0.dtd
PUBLIC "-//IETF//DTD HTML Level 0//EN//2.0" html-0.dtd
-- ISO latin 1 entity set for HTML --
PUBLIC "-//IETF//ENTITIES Added Latin 1//EN" ISOlat1.sgml
5.2 HTML DTD
This is the Document Type Definition for the
HyperText Markup Language (HTML DTD):
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<!-- html.dtd
Document Type Definition for the HyperText Markup Language
(HTML DTD)
$Id: html.dtd,v 1.24 1995/02/06 21:28:45 connolly Exp $
Author: Daniel W. Connolly <connolly@hal.com>
See Also: html.decl, html-0.dtd, html-1.dtd
http://www.hal.com/%7Econnolly/html-spec/index.html
http://info.cern.ch/hypertext/WWW/MarkUp2/MarkUp.html
-->
<!ENTITY % HTML.Version
"-//IETF//DTD HTML 2.0//EN"
-- Typical usage:
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
...
</html>
--
>
<!--============ Feature Test Entities ========================-->
<!ENTITY % HTML.Recommended "IGNORE"
-- Certain features of the language are necessary for
compatibility with widespread usage, but they may
compromise the structural integrity of a document.
This feature test entity enables a more prescriptive
document type definition that eliminates
those features.
-->
<![ %HTML.Recommended [
<!ENTITY % HTML.Deprecated "IGNORE">
]]>
<!ENTITY % HTML.Deprecated "INCLUDE"
-- Certain features of the language are necessary for
compatibility with earlier versions of the specification,
but they tend to be used an implemented inconsistently,
and their use is deprecated. This feature test entity
enables a document type definition that eliminates
these features.
-->
Berners-Lee, Connolly, et. al. Page 59
HTML 2.0 February 8, 1995
<!ENTITY % HTML.Highlighting "INCLUDE"
-- Use this feature test entity to validate that a
document uses no highlighting tags, which may be
ignored on minimal implementations.
-->
<!ENTITY % HTML.Forms "INCLUDE"
-- Use this feature test entity to validate that a document
contains no forms, which may not be supported in minimal
implementations
-->
<!--============== Imported Names ==============================-->
<!ENTITY % Content-Type "CDATA"
-- meaning an internet media type
(aka MIME content type, as per RFC1521)
-->
<!ENTITY % HTTP-Method "GET | POST"
-- as per HTTP specification, in progress
-->
<!ENTITY % URI "CDATA"
-- The term URI means a CDATA attribute
whose value is a Uniform Resource Identifier,
as defined by
"Universal Resource Identifiers" by Tim Berners-Lee
aka RFC 1630
Note that CDATA attributes are limited by the LITLEN
capacity (1024 in the current version of html.decl),
so that URIs in HTML have a bounded length.
-->
<!--========= DTD "Macros" =====================-->
<!ENTITY % heading "H1|H2|H3|H4|H5|H6">
<!ENTITY % list " UL | OL | DIR | MENU " >
<!--======= Character mnemonic entities =================-->
<!ENTITY % ISOlat1 PUBLIC
"ISO 8879-1986//ENTITIES Added Latin 1//EN//HTML">
%ISOlat1;
Berners-Lee, Connolly, et. al. Page 60
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<!ENTITY amp CDATA "&" -- ampersand -->
<!ENTITY gt CDATA ">" -- greater than -->
<!ENTITY lt CDATA "<" -- less than -->
<!ENTITY quot CDATA """ -- double quote -->
<!--========= SGML Document Access (SDA) Parameter Entities =====-->
<!-- HTML 2.0 contains SGML Document Access (SDA) fixed attributes
in support of easy transformation to the International Committee
for Accessible Document Design (ICADD) DTD
"-//EC-USA-CDA/ICADD//DTD ICADD22//EN".
ICADD applications are designed to support usable access to
structured information by print-impaired individuals through
Braille, large print and voice synthesis. For more information on
SDA & ICADD:
- ISO 12083:1993, Annex A.8, Facilities for Braille,
large print and computer voice
- ICADD ListServ
<ICADD%ASUACAD.BITNET@ARIZVM1.ccit.arizona.edu>
- Usenet news group bit.listserv.easi
- Recording for the Blind, +1 800 221 4792
-->
<!ENTITY % SDAFORM "SDAFORM CDATA #FIXED"
-- one to one mapping -->
<!ENTITY % SDARULE "SDARULE CDATA #FIXED"
-- context-sensitive mapping -->
<!ENTITY % SDAPREF "SDAPREF CDATA #FIXED"
-- generated text prefix -->
<!ENTITY % SDASUFF "SDASUFF CDATA #FIXED"
-- generated text suffix -->
<!ENTITY % SDASUSP "SDASUSP NAME #FIXED"
-- suspend transform process -->
<!--========== Text Markup =====================-->
<![ %HTML.Highlighting [
<!ENTITY % font " TT | B | I ">
<!ENTITY % phrase "EM | STRONG | CODE | SAMP | KBD | VAR | CITE ">
<!ENTITY % text "#PCDATA | A | IMG | BR | %phrase | %font">
<!ELEMENT (%font;|%phrase) - - (%text)*>
<!ATTLIST ( TT | CODE | SAMP | KBD | VAR )
%SDAFORM; "Lit"
>
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<!ATTLIST ( B | STRONG )
%SDAFORM; "B"
>
<!ATTLIST ( I | EM | CITE )
%SDAFORM; "It"
>
<!-- <TT> Typewriter text -->
<!-- <B> Bold text -->
<!-- <I> Italic text -->
<!-- <EM> Emphasized phrase -->
<!-- <STRONG> Strong emphais -->
<!-- <CODE> Source code phrase -->
<!-- <SAMP> Sample text or characters -->
<!-- <KBD> Keyboard phrase, e.g. user input -->
<!-- <VAR> Variable phrase or substituable -->
<!-- <CITE> Name or title of cited work -->
<!ENTITY % pre.content "#PCDATA | A | HR | BR | %font | %phrase">
]]>
<!ENTITY % text "#PCDATA | A | IMG | BR">
<!ELEMENT BR - O EMPTY>
<!ATTLIST BR
%SDAPREF; "&#RE;"
>
<!-- <BR> Line break -->
<!--========= Link Markup ======================-->
<![ %HTML.Recommended [
<!ENTITY % linkName "ID">
]]>
<!ENTITY % linkName "CDATA">
<!ENTITY % linkType "NAME"
-- a list of these will be specified at a later date -->
<!ENTITY % linkExtraAttributes
"REL %linkType #IMPLIED
REV %linkType #IMPLIED
URN CDATA #IMPLIED
TITLE CDATA #IMPLIED
METHODS NAMES #IMPLIED
Berners-Lee, Connolly, et. al. Page 62
HTML 2.0 February 8, 1995
">
<![ %HTML.Recommended [
<!ENTITY % A.content "(%text)*"
-- <H1><a name="xxx">Heading</a></H1>
is preferred to
<a name="xxx"><H1>Heading</H1></a>
-->
]]>
<!ENTITY % A.content "(%heading|%text)*">
<!ELEMENT A - - %A.content -(A)>
<!ATTLIST A
HREF %URI #IMPLIED
NAME %linkName #IMPLIED
%linkExtraAttributes;
%SDAPREF; "<Anchor: #AttList>"
>
<!-- <A> Anchor; source/destination of link -->
<!-- <A NAME="..."> Name of this anchor -->
<!-- <A HREF="..."> Address of link destination -->
<!-- <A URN="..."> Permanent address of destination -->
<!-- <A REL=...> Relationship to destination -->
<!-- <A REV=...> Relationship of destination to this -->
<!-- <A TITLE="..."> Title of destination (advisory) -->
<!-- <A METHODS="..."> Operations on destination (advisory) -->
<!--========== Images ==========================-->
<!ELEMENT IMG - O EMPTY>
<!ATTLIST IMG
SRC %URI; #REQUIRED
ALT CDATA #IMPLIED
ALIGN (top|middle|bottom) #IMPLIED
ISMAP (ISMAP) #IMPLIED
%SDAPREF; "<Fig><?SDATrans Img: #AttList>#AttVal(Alt)</Fig>"
>
<!-- <IMG> Image; icon, glyph or illustration -->
<!-- <IMG SRC="..."> Address of image object -->
<!-- <IMG ALT="..."> Textual alternative -->
<!-- <IMG ALIGN=...> Position relative to text -->
<!-- <IMG ISMAP> Each pixel can be a link -->
<!--========== Paragraphs=======================-->
<!ELEMENT P - O (%text)*>
<!ATTLIST P
Berners-Lee, Connolly, et. al. Page 63
HTML 2.0 February 8, 1995
%SDAFORM; "Para"
>
<!-- <P> Paragraph -->
<!--========== Headings, Titles, Sections ===============-->
<!ELEMENT HR - O EMPTY>
<!ATTLIST HR
%SDAPREF; "&#RE;&#RE;"
>
<!-- <HR> Horizontal rule -->
<!ELEMENT ( %heading ) - - (%text;)*>
<!ATTLIST H1
%SDAFORM; "H1"
>
<!ATTLIST H2
%SDAFORM; "H2"
>
<!ATTLIST H3
%SDAFORM; "H3"
>
<!ATTLIST H4
%SDAFORM; "H4"
>
<!ATTLIST H5
%SDAFORM; "H5"
>
<!ATTLIST H6
%SDAFORM; "H6"
>
<!-- <H1> Heading, level 1 -->
<!-- <H2> Heading, level 2 -->
<!-- <H3> Heading, level 3 -->
<!-- <H4> Heading, level 4 -->
<!-- <H5> Heading, level 5 -->
<!-- <H6> Heading, level 6 -->
<!--========== Text Flows ======================-->
<![ %HTML.Forms [
<!ENTITY % block.forms "BLOCKQUOTE | FORM | ISINDEX">
]]>
<!ENTITY % block.forms "BLOCKQUOTE">
Berners-Lee, Connolly, et. al. Page 64
HTML 2.0 February 8, 1995
<![ %HTML.Deprecated [
<!ENTITY % preformatted "PRE | XMP | LISTING">
]]>
<!ENTITY % preformatted "PRE">
<!ENTITY % block "P | %list | DL
| %preformatted
| %block.forms">
<!ENTITY % flow "(%text|%block)*">
<!ENTITY % pre.content "#PCDATA | A | HR | BR">
<!ELEMENT PRE - - (%pre.content)*>
<!ATTLIST PRE
WIDTH NUMBER #implied
%SDAFORM; "Lit"
>
<!-- <PRE> Preformatted text -->
<!-- <PRE WIDTH=...> Maximum characters per line -->
<![ %HTML.Deprecated [
<!ENTITY % literal "CDATA"
-- historical, non-conforming parsing mode where
the only markup signal is the end tag
in full
-->
<!ELEMENT (XMP|LISTING) - - %literal>
<!ATTLIST XMP
%SDAFORM; "Lit"
%SDAPREF; "Example:&#RE;"
>
<!ATTLIST LISTING
%SDAFORM; "Lit"
%SDAPREF; "Listing:&#RE;"
>
<!-- <XMP> Example section -->
<!-- <LISTING> Computer listing -->
<!ELEMENT PLAINTEXT - O %literal>
<!-- <PLAINTEXT> Plain text passage -->
<!ATTLIST PLAINTEXT
%SDAFORM; "Lit"
>
Berners-Lee, Connolly, et. al. Page 65
HTML 2.0 February 8, 1995
]]>
<!--========== Lists ==================-->
<!ELEMENT DL - - (DT | DD)+>
<!ATTLIST DL
COMPACT (COMPACT) #IMPLIED
%SDAFORM; "List"
%SDAPREF; "Definition List:"
>
<!ELEMENT DT - O (%text)*>
<!ATTLIST DT
%SDAFORM; "Term"
>
<!ELEMENT DD - O %flow>
<!ATTLIST DD
%SDAFORM; "LItem"
>
<!-- <DL> Definition list, or glossary -->
<!-- <DL COMPACT> Compact style list -->
<!-- <DT> Term in definition list -->
<!-- <DD> Definition of term -->
<!ELEMENT (OL|UL) - - (LI)+>
<!ATTLIST OL
COMPACT (COMPACT) #IMPLIED
%SDAFORM; "List"
>
<!ATTLIST UL
COMPACT (COMPACT) #IMPLIED
%SDAFORM; "List"
>
<!-- <UL> Unordered list -->
<!-- <UL COMPACT> Compact list style -->
<!-- <OL> Ordered, or numbered list -->
<!-- <OL COMPACT> Compact list style -->
<!ELEMENT (DIR|MENU) - - (LI)+ -(%block)>
<!ATTLIST DIR
COMPACT (COMPACT) #IMPLIED
%SDAFORM; "List"
%SDAPREF; "<LHead>Directory</LHead>"
>
<!ATTLIST MENU
COMPACT (COMPACT) #IMPLIED
Berners-Lee, Connolly, et. al. Page 66
HTML 2.0 February 8, 1995
%SDAFORM; "List"
%SDAPREF; "<LHead>Menu</LHead>"
>
<!-- <DIR> Directory list -->
<!-- <DIR COMPACT> Compact list style -->
<!-- <MENU> Menu list -->
<!-- <MENU COMPACT> Compact list style -->
<!ELEMENT LI - O %flow>
<!ATTLIST LI
%SDAFORM; "LItem"
>
<!-- <LI> List item -->
<!--========== Document Body ===================-->
<![ %HTML.Recommended [
<!ENTITY % body.content "(%heading|%block|HR|ADDRESS|IMG)*"
-- <h1>Heading</h1>
<p>Text ...
is preferred to
<h1>Heading</h1>
Text ...
-->
]]>
<!ENTITY % body.content "(%heading | %text | %block |
HR | ADDRESS)*">
<!ELEMENT BODY O O %body.content>
<!-- <BODY> Document body -->
<!ELEMENT BLOCKQUOTE - - %body.content>
<!ATTLIST BLOCKQUOTE
%SDAFORM; "BQ"
>
<!-- <BLOCKQUOTE> Quoted passage -->
<!ELEMENT ADDRESS - - (%text|P)*>
<!ATTLIST ADDRESS
%SDAFORM; "Lit"
%SDAPREF; "Address:&#RE;"
>
<!-- <ADDRESS> Address, signature, or byline -->
Berners-Lee, Connolly, et. al. Page 67
HTML 2.0 February 8, 1995
<!--======= Forms ====================-->
<![ %HTML.Forms [
<!ELEMENT FORM - - %body.content -(FORM) +(INPUT|SELECT|TEXTAREA)>
<!ATTLIST FORM
ACTION %URI #IMPLIED
METHOD (%HTTP-Method) GET
ENCTYPE %Content-Type; "application/x-www-form-urlencoded"
%SDAPREF; "<Para>Form:</Para>"
%SDASUFF; "<Para>Form End.</Para>"
>
<!-- <FORM> Fill-out or data-entry form -->
<!-- <FORM ACTION="..."> Address for completed form -->
<!-- <FORM METHOD=...> Method of submitting form -->
<!-- <FORM ENCTYPE="..."> Representation of form data -->
<!ENTITY % InputType "(TEXT | PASSWORD | CHECKBOX |
RADIO | SUBMIT | RESET |
IMAGE | HIDDEN )">
<!ELEMENT INPUT - O EMPTY>
<!ATTLIST INPUT
TYPE %InputType TEXT
NAME CDATA #IMPLIED
VALUE CDATA #IMPLIED
SRC %URI #IMPLIED
CHECKED (CHECKED) #IMPLIED
SIZE CDATA #IMPLIED
MAXLENGTH NUMBER #IMPLIED
ALIGN (top|middle|bottom) #IMPLIED
%SDAPREF; "Input: "
>
<!-- <INPUT> Form input datum -->
<!-- <INPUT TYPE=...> Type of input interaction -->
<!-- <INPUT NAME=...> Name of form datum -->
<!-- <INPUT VALUE="..."> Default/initial/selected value -->
<!-- <INPUT SRC="..."> Address of image -->
<!-- <INPUT CHECKED> Initial state is "on" -->
<!-- <INPUT SIZE=...> Field size hint -->
<!-- <INPUT MAXLENGTH=...> Data length maximum -->
<!-- <INPUT ALIGN=...> Image alignment -->
<!ELEMENT SELECT - - (OPTION+) -(INPUT|SELECT|TEXTAREA)>
<!ATTLIST SELECT
NAME CDATA #REQUIRED
SIZE NUMBER #IMPLIED
MULTIPLE (MULTIPLE) #IMPLIED
Berners-Lee, Connolly, et. al. Page 68
HTML 2.0 February 8, 1995
%SDAFORM; "List"
%SDAPREF;
"<LHead>Select #AttVal(Multiple)</LHead>"
>
<!-- <SELECT> Selection of option(s) -->
<!-- <SELECT NAME=...> Name of form datum -->
<!-- <SELECT SIZE=...> Options displayed at a time -->
<!-- <SELECT MULTIPLE> Multiple selections allowed -->
<!ELEMENT OPTION - O (#PCDATA)*>
<!ATTLIST OPTION
SELECTED (SELECTED) #IMPLIED
VALUE CDATA #IMPLIED
%SDAFORM; "LItem"
%SDAPREF;
"Option: #AttVal(Value) #AttVal(Selected)"
>
<!-- <OPTION> A selection option -->
<!-- <OPTION SELECTED> Initial state -->
<!-- <OPTION VALUE="..."> Form datum value for this option-->
<!ELEMENT TEXTAREA - - (#PCDATA)* -(INPUT|SELECT|TEXTAREA)>
<!ATTLIST TEXTAREA
NAME CDATA #REQUIRED
ROWS NUMBER #REQUIRED
COLS NUMBER #REQUIRED
%SDAFORM; "Para"
%SDAPREF; "Input Text -- #AttVal(Name): "
>
<!-- <TEXTAREA> An area for text input -->
<!-- <TEXTAREA NAME=...> Name of form datum -->
<!-- <TEXTAREA ROWS=...> Height of area -->
<!-- <TEXTAREA COLS=...> Width of area -->
]]>
<!--======= Document Head ======================-->
<![ %HTML.Recommended [
<!ENTITY % head.extra "META* & LINK*">
]]>
<!ENTITY % head.extra "NEXTID? & META* & LINK*">
<!ENTITY % head.content "TITLE & ISINDEX? & BASE? &
(%head.extra)">
Berners-Lee, Connolly, et. al. Page 69
HTML 2.0 February 8, 1995
<!ELEMENT HEAD O O (%head.content)>
<!-- <HEAD> Document head -->
<!ELEMENT TITLE - - (#PCDATA)*>
<!ATTLIST TITLE
%SDAFORM; "Ti" >
<!-- <TITLE> Title of document -->
<!ELEMENT LINK - O EMPTY>
<!ATTLIST LINK
HREF %URI #REQUIRED
%linkExtraAttributes;
%SDAPREF; "Linked to : #AttVal (TITLE) (URN) (HREF)>" >
<!-- <LINK> Link from this document -->
<!-- <LINK HREF="..."> Address of link destination -->
<!-- <LINK URN="..."> Lasting name of destination -->
<!-- <LINK REL=...> Relationship to destination -->
<!-- <LINK REV=...> Relationship of destination to this -->
<!-- <LINK TITLE="..."> Title of destination (advisory) -->
<!-- <LINK METHODS="..."> Operations allowed (advisory) -->
<!ELEMENT ISINDEX - O EMPTY>
<!ATTLIST ISINDEX
%SDAPREF;
"<Para>[Document is indexed/searchable.]</Para>">
<!-- <ISINDEX> Document is a searchable index -->
<!ELEMENT BASE - O EMPTY>
<!ATTLIST BASE
HREF %URI; #REQUIRED >
<!-- <BASE> Base context document -->
<!-- <BASE HREF="..."> Address for this document -->
<!ELEMENT NEXTID - O EMPTY>
<!ATTLIST NEXTID
N %linkName #REQUIRED >
<!-- <NEXTID> Next ID to use for link name -->
<!-- <NEXTID N=...> Next ID to use for link name -->
<!ELEMENT META - O EMPTY>
<!ATTLIST META
HTTP-EQUIV NAME #IMPLIED
NAME NAME #IMPLIED
Berners-Lee, Connolly, et. al. Page 70
HTML 2.0 February 8, 1995
CONTENT CDATA #REQUIRED >
<!-- <META> Generic Metainformation -->
<!-- <META HTTP-EQUIV=...> HTTP response header name -->
<!-- <META HTTP-EQUIV=...> Metainformation name -->
<!-- <META CONTENT="..."> Associated information -->
<!--======= Document Structure =================-->
<![ %HTML.Deprecated [
<!ENTITY % html.content "HEAD, BODY, PLAINTEXT?">
]]>
<!ENTITY % html.content "HEAD, BODY">
<!ELEMENT HTML O O (%html.content)>
<!ENTITY % version.attr "VERSION CDATA #FIXED '%HTML.Version;'">
<!ATTLIST HTML
%version.attr;
%SDAFORM; "Book"
>
<!-- <HTML> HTML Document -->
5.2.1 ISO Latin 1 Definitions for HTML
<!-- (C) International Organization for Standardization 1986
Permission to copy in any form is granted for use with
conforming SGML systems and applications as defined in
ISO 8879:1986, provided this notice is included in all copies.
-->
<!-- Character entity set. Typical invocation:
<!ENTITY % ISOlat1 PUBLIC
"-//IETF//ENTITIES Added Latin 1 for HTML//EN">
%ISOlat1;
-->
<!-- Modified for use in HTML
$Id: ISOlat1.sgml,v 1.1 1994/09/24 14:06:34 connolly Exp $ -->
<!ENTITY AElig CDATA "Æ" -- capital AE diphthong (ligature) -->
<!ENTITY Aacute CDATA "Á" -- capital A, acute accent -->
<!ENTITY Acirc CDATA "Â" -- capital A, circumflex accent -->
<!ENTITY Agrave CDATA "À" -- capital A, grave accent -->
<!ENTITY Aring CDATA "Å" -- capital A, ring -->
<!ENTITY Atilde CDATA "Ã" -- capital A, tilde -->
<!ENTITY Auml CDATA "Ä" -- capital A, dieresis or umlaut mark -->
<!ENTITY Ccedil CDATA "Ç" -- capital C, cedilla -->
<!ENTITY ETH CDATA "Ð" -- capital Eth, Icelandic -->
<!ENTITY Eacute CDATA "É" -- capital E, acute accent -->
<!ENTITY Ecirc CDATA "Ê" -- capital E, circumflex accent -->
<!ENTITY Egrave CDATA "È" -- capital E, grave accent -->
Berners-Lee, Connolly, et. al. Page 71
HTML 2.0 February 8, 1995
<!ENTITY Euml CDATA "Ë" -- capital E, dieresis or umlaut mark -->
<!ENTITY Iacute CDATA "Í" -- capital I, acute accent -->
<!ENTITY Icirc CDATA "Î" -- capital I, circumflex accent -->
<!ENTITY Igrave CDATA "Ì" -- capital I, grave accent -->
<!ENTITY Iuml CDATA "Ï" -- capital I, dieresis or umlaut mark -->
<!ENTITY Ntilde CDATA "Ñ" -- capital N, tilde -->
<!ENTITY Oacute CDATA "Ó" -- capital O, acute accent -->
<!ENTITY Ocirc CDATA "Ô" -- capital O, circumflex accent -->
<!ENTITY Ograve CDATA "Ò" -- capital O, grave accent -->
<!ENTITY Oslash CDATA "Ø" -- capital O, slash -->
<!ENTITY Otilde CDATA "Õ" -- capital O, tilde -->
<!ENTITY Ouml CDATA "Ö" -- capital O, dieresis or umlaut mark -->
<!ENTITY THORN CDATA "Þ" -- capital THORN, Icelandic -->
<!ENTITY Uacute CDATA "Ú" -- capital U, acute accent -->
<!ENTITY Ucirc CDATA "Û" -- capital U, circumflex accent -->
<!ENTITY Ugrave CDATA "Ù" -- capital U, grave accent -->
<!ENTITY Uuml CDATA "Ü" -- capital U, dieresis or umlaut mark -->
<!ENTITY Yacute CDATA "Ý" -- capital Y, acute accent -->
<!ENTITY aacute CDATA "á" -- small a, acute accent -->
<!ENTITY acirc CDATA "â" -- small a, circumflex accent -->
<!ENTITY aelig CDATA "æ" -- small ae diphthong (ligature) -->
<!ENTITY agrave CDATA "à" -- small a, grave accent -->
<!ENTITY aring CDATA "å" -- small a, ring -->
<!ENTITY atilde CDATA "ã" -- small a, tilde -->
<!ENTITY auml CDATA "ä" -- small a, dieresis or umlaut mark -->
<!ENTITY ccedil CDATA "ç" -- small c, cedilla -->
<!ENTITY eacute CDATA "é" -- small e, acute accent -->
<!ENTITY ecirc CDATA "ê" -- small e, circumflex accent -->
<!ENTITY egrave CDATA "è" -- small e, grave accent -->
<!ENTITY eth CDATA "ð" -- small eth, Icelandic -->
<!ENTITY euml CDATA "ë" -- small e, dieresis or umlaut mark -->
<!ENTITY iacute CDATA "í" -- small i, acute accent -->
<!ENTITY icirc CDATA "î" -- small i, circumflex accent -->
<!ENTITY igrave CDATA "ì" -- small i, grave accent -->
<!ENTITY iuml CDATA "ï" -- small i, dieresis or umlaut mark -->
<!ENTITY ntilde CDATA "ñ" -- small n, tilde -->
<!ENTITY oacute CDATA "ó" -- small o, acute accent -->
<!ENTITY ocirc CDATA "ô" -- small o, circumflex accent -->
<!ENTITY ograve CDATA "ò" -- small o, grave accent -->
<!ENTITY oslash CDATA "ø" -- small o, slash -->
<!ENTITY otilde CDATA "õ" -- small o, tilde -->
<!ENTITY ouml CDATA "ö" -- small o, dieresis or umlaut mark -->
<!ENTITY szlig CDATA "ß" -- small sharp s, German(sz ligature)-->
<!ENTITY thorn CDATA "þ" -- small thorn, Icelandic -->
<!ENTITY uacute CDATA "ú" -- small u, acute accent -->
<!ENTITY ucirc CDATA "û" -- small u, circumflex accent -->
<!ENTITY ugrave CDATA "ù" -- small u, grave accent -->
<!ENTITY uuml CDATA "ü" -- small u, dieresis or umlaut mark -->
<!ENTITY yacute CDATA "ý" -- small y, acute accent -->
<!ENTITY yuml CDATA "ÿ" -- small y, dieresis or umlaut mark -->
Berners-Lee, Connolly, et. al. Page 72
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5.3 HTML Level 0 DTD
This is the Document Type Definition for the HyperText
Markup Language as used by minimally conforming World Wide
Web applications (HTML Level 0 DTD):
<!-- html-0.dtd
Document Type Definition for the HyperText Markup Language
as used by minimally conforming World Wide Web applications
(HTML Level 0 DTD).
$Id: html-0.dtd,v 1.11 1995/01/28 05:59:32 connolly Exp $
Author: Daniel W. Connolly <connolly@hal.com>
See Also: http://www.hal.com/%7Econnolly/html-spec/index.html
http://info.cern.ch/hypertext/WWW/MarkUp2/MarkUp.html
-->
<!ENTITY % HTML.Version
"-//IETF//DTD HTML 2.0 Level 0//EN"
-- public identifier for "minimal conformance" version --
-- Typical usage:
<!DOCTYPE HTML PUBLIC
"-//IETF//DTD HTML Level 0//EN">
<html>
...
</html>
--
>
<!-- Feature Test Entities -->
<!ENTITY % HTML.Highlighting "IGNORE">
<!ENTITY % HTML.Forms "IGNORE">
<!ENTITY % head.extra " ">
<!ENTITY % linkExtraAttributes " ">
<!ENTITY % html PUBLIC "-//IETF//DTD HTML 2.0//EN">
%html;
5.4 HTML Level 1 DTD
This is the Document Type Definition for the HyperText
Markup Language with Level 1 Extensions (HTML Level 1 DTD):
Berners-Lee, Connolly, et. al. Page 73
HTML 2.0 February 8, 1995
<!-- html-1.dtd
Document Type Definition for the HyperText Markup Language
with Level 1 Extensions (HTML Level 1 DTD).
$Id: html-1.dtd,v 1.6 1994/11/30 23:45:26 connolly Exp $
Author: Daniel W. Connolly <connolly@hal.com>
See Also: http://www.hal.com/%7Econnolly/html-spec/index.html
http://info.cern.ch/hypertext/WWW/MarkUp2/MarkUp.html
-->
<!ENTITY % HTML.Version
"-//IETF//DTD HTML 2.0 Level 1//EN"
-- Typical usage:
<!DOCTYPE HTML PUBLIC
"-//IETF//DTD HTML Level 1//EN">
<html>
...
</html>
--
>
<!-- Feature Test Entities -->
<!ENTITY % HTML.Forms "IGNORE">
<!ENTITY % html PUBLIC "-//IETF//DTD HTML 2.0//EN">
%html;
7. Glossary
The HTML specification uses these words with precise
meanings:
attribute
A syntactical component of an HTML element which is
often used to specify a characteristic quality of an
element, other than type or content.
document type definition (DTD)
A DTD is a collection of declarations (entity, element,
attribute, link, map, etc.) in SGML syntax that defines
the components and structures available for a class
(type) of documents.
element
Berners-Lee, Connolly, et. al. Page 74
HTML 2.0 February 8, 1995
A component of the hierarchical structure defined by the
document type definition; it is identified in a document
instance by descriptive markup, usually a start-tag and
an end-tag.
HTML
HyperText Markup Language.
HTML user agent
Any tool used with HTML documents.
HTML document
A collection of information represented as a sequence of
characters. An HTML document consists of data characters
and markup. In particular, the markup describes a
structure conforming to the HTML document type
definition.
HTTP
A generic stateless object-oriented protocol, which may
be used for many similar tasks by extending the
commands, or "methods", used. For example, you might use
HTTP for name servers and distributed object-oriented
systems, With HTTP, the negotiation of data
representation allows systems to be built independent of
the development of new representations. For more
information see:
http://info.cern.ch/hypertext/WWW/Protocols/HTTP/HTTP2.html
(document) instance
The document itself including the actual content with
the actual markup. Can be a single document or part of a
document instance set that follows the DTD.
markup
Text added to the data of a document to convey
information about it. There are four different kinds of
markup: descriptive markup (tags), references, markup
declarations, and processing instructions.
Multipurpose Internet Mail Extensions (MIME)
An extension to Internet email which provides the
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HTML 2.0 February 8, 1995
ability to transfer non-textual data, such as graphics,
audio and fax. It is defined in RFC 1341.
representation
The encoding of information for interchange. For
example, HTML is a representation of hypertext.
rendering
Formatting and presenting information.
SGML
Standard Generalized Markup Language is a data encoding
that allows the information in documents to be shared -
either by other document publishing systems or by
applications for electronic delivery, configuration
management, database management, inventory control, etc.
Defined in ISO 8879:1986 Information Processing Text and
Office Systems; Standard Generalized Markup Language
(SGML).
SGMLS
An SGML parser by James Clark, jjc@jclark.com, derived
from the ARCSGML parser materials which were written by
Charles F. Goldfarb. The source is available at
ftp.ifi.uio.no/pub/SGML/SGMLS.
tag
Descriptive markup. There are two kinds of tags; start-
tags and end-tags.
URI
Universal Resource Identifiers (URIs) is the name for a
generic WWW identifier. The URI specification simply
defines the syntax for encoding arbitrary naming or
addressing schemes, and has a list of such schemes. See
also: http://info.cern.ch/hypertext/WWW/Addressing/Addressing.html
WWW
A hypertext-based, distributed information system
created by researchers at CERN in Switzerland. Users may
create, edit or browse hypertext documents. The clients
and servers are freely available.See also:
http://info.cern.ch/hypertext/WWW/TheProject.html
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7.1 Imperatives
may
The implementation is not obliged to follow this in any
way.
must
If this is not followed, the implementation does not
conform to this specification.
shall
If this is not followed, the implementation does not
conform to this specification.
should
If this is not followed, though the implementation
officially conforms to the specification, undesirable
results may occur in practice.
typical
Typical rendering is described for many elements. This
is not a mandatory part of the specification but is
given as guidance for designers and to help explain the
uses for which the elements were intended.
8. References
The HTML specification cites these works:
HTTP
HTTP: A Protocol for Networked Information. This
document is available at
http://info.cern.ch/hypertext/WWW/Protocols/HTTP/HTTP2.h
tml.
MIME
N. Borenstein, N. Freed, MIME (Multipurpose Internet
Mail Extensions) Part One: Mechanisms for Specifying and
Describing the Format of Internet Message Bodies,
09/23/1993. (Pages=81) (Format=.txt, .ps) (Obsoletes
RFC1341) (Updated by RFC1590).
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SGML
ISO Standard 8879:1986 Information Processing Text and
Office Systems; Standard Generalized Markup Language
(SGML).
SGMLS
An SGML parser by James Clark, jjc@jclark.com, derived
from the ARCSGML parser materials which were written by
Charles F. Goldfarb. The source is available at
ftp.ifi.uio.no/pub/SGML/SGMLS.
URI
Universal Resource Identifiers. Available by anonymous
FTP as Postscript (info.cern.ch/pub/www/doc/url.ps) or
text (info.cern.ch/pub/www/doc/url.txt)
WWW
The World Wide Web , a global information initiative.
For bootstrap information, telnet info.cern.ch or find
documents by ftp://info.cern.ch/pub/www/doc.
9. Acknowledgments
The HTML document type was designed by Tim Berners-Lee
at CERN as part of the 1990 World Wide Web project. In
1992, Dan Connolly wrote the HTML Document Type
Definition (DTD) and a brief HTML specification.
Since 1993, a wide variety of Internet participants have
contributed to the evolution of HTML, which has included
the addition of in-line images introduced by the NCSA
Mosaic software for WWW. Dave Raggett played an
important role in deriving the FORMS material from the
HTML+ specification.
Dan Connolly and Karen Olson Muldrow rewrote the HTML
Specification in 1994.
Special thanks to the many people who have contributed
to this specification:
- Terry Allen; O'Reilly & Associates; terry@ora.com
- Marc Andreessen; Netscape Communications Corp;
marca@mcom.com
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HTML 2.0 February 8, 1995
- Paul Burchard; The Geometry Center, University of
Minnesota; burchard@geom.umn.edu
- James Clark; jjc@jclark.com
- Daniel W. Connolly; HaL Computer Systems; connolly@hal.com
- Roy Fielding; University of California, Irvine;
fielding@ics.uci.edu
- Peter Flynn; University College Cork, Ireland; pflynn@www.ucc.ie
- Jay Glicksman; Enterprise Integration Technology; jay@eit.com
- Paul Grosso; ArborText, Inc.; paul@arbortext.com
- Eduardo Gutentag; Sun Microsystems; eduardo@Eng.Sun.com
- Bill Hefley; Software Engineering Institute,
Carnegie Mellon University; weh@sei.cmu.edu
- Chung-Jen Ho; Xerox Corporation; cho@xsoft.xerox.com
- Mike Knezovich; Spyglass, Inc.; mike@spyglass.com
- Tim Berners-Lee; CERN; timbl@info.cern.ch
- Tom Magliery; NCSA; mag@ncsa.uiuc.edu
- Murray Maloney; Toronto Development Centre, The
Santa Cruz Operation (SCO); murray@sco.com
- Larry Masinter; Xerox Palo Alto Research Center;
masinter@parc.xerox.com
- Karen Olson Muldrow; HaL Computer Systems; karen@hal.com
- Bill Perry, Spry, Inc., wmperry@spry.com
- Dave Raggett, Hewlett Packard, dsr@hplb.hpl.hp.com
- E. Corprew Reed; Cold Spring Harbor Laboratory; corp@cshl.org
- Yuri Rubinsky; SoftQuad, Inc.; yuri@sq.com
- Eric Schieler; Spyglass, Inc.; eschieler@spyglass.com
- James L. Seidman; Spyglass, Inc.; jim@spyglass.com
- Eric W. Sink; Spyglass, Inc.; eric@spyglass.com
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- Stuart Weibel; OCLC Office of Research; weibel@oclc.org
- Chris Wilson; Spry, Inc.; cwilson@spry.com
10. Author's Addresses
Tim Berners-Lee
timbl@quag.lcs.mit.edu
Daniel W. Connolly
Hal Software Systems
3006A Longhorn Blvd.
Austin, TX 78758
phone: (512) 834-9962 extension 5010
fax: (512) 823-9963
URL: http://www.hal.com/~connolly
email: connolly@hal.com
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