REC-html32

W3C Recommendation 14-Jan-1997

Superseded 15-March-2018

Author: Dave Raggett <dsr@w3.org>

---

Status of this document

This document has been reviewed by W3C members and other interested parties and has been endorsed by the Director as a W3C Recommendation.

This specification is a Superseded Recommendation. A newer specification exists that is recommended for new adoption in place of this specification. New implementations should follow the latest version of the HTML specification.

A list of current W3C Recommendations and other technical documents can be found at https://www.w3.org/TR/.

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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. This specification defines HTML version 3.2. HTML 3.2 aims to capture recommended practice as of early ’96 and as such to be used as a replacement for HTML 2.0 (RFC 1866).

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Contents

• Introduction to HTML 3.2
• HTML as an SGML application
• The Structure of HTML documents
• The HEAD element and its children
• The BODY element and its children
• Sample SGML Open Catalog for HTML 3.2
• SGML Declaration for HTML 3.2
• HTML 3.2 Document Type Definition
• Character Entities for ISO Latin-1
• Table of printable Latin-1 Character codes
• Acknowledgements
• Further Reading ...

---

Introduction to HTML 3.2

HTML 3.2 is W3C’s specification for HTML, developed in early `96 together with vendors including IBM, Microsoft, Netscape Communications Corporation, Novell, SoftQuad, Spyglass, and Sun Microsystems. HTML 3.2 adds widely deployed features such as tables, applets and text flow around images, while providing full backwards compatibility with the existing standard HTML 2.0.

W3C is continuing to work with vendors on extensions for accessibility features, multimedia objects, scripting, style sheets, layout, forms, math and internationalization. W3C plans on incorporating this work in further versions of HTML.

HTML as an SGML Application

HTML 3.2 is an SGML application conforming to International Standard ISO 8879 – Standard Generalized Markup Language. As an SGML application, the syntax of conforming HTML 3.2 documents is defined by the combination of the SGML declaration and the document type definition (DTD). This specification defines the intended interpretation of HTML 3.2 elements, and places further constraints on the permitted syntax which are otherwise inexpressible in the DTD.

The SGML rules for record boundaries are tricky. In particular, a record end immediately following a start tag should be discarded. For example:

<P>
Text

is equivalent to:

<P>Text

Similarly, a record end immediately preceding an end tag should be discarded. For example:

Text
</P>

is equivalent to:

Text</P>

Except within literal text (e.g. the PRE element), HTML treats contiguous sequences of white space characters as being equivalent to a single space character (ASCII decimal 32). These rules allow authors considerable flexibility when editing the marked-up text directly. Note that future revisions to HTML may allow for the interpretation of the horizontal tab character (ASCII decimal 9) with respect to a tab rule defined by an associated style sheet.

SGML entities in PCDATA content or in CDATA attributes are expanded by the parser, e.g. &#233; is expanded to the ISO Latin-1 character decimal 233 (a lower case letter e with an acute accent). This could also have been written as a named character entity, e.g. é. The & character can be included in its own right using the named character entity &.

HTML allows CDATA attributes to be unquoted provided the attribute value contains only letters (a to z and A to Z), digits (0 to 9), hyphens (ASCII decimal 45) or, periods (ASCII decimal 46). Attribute values can be quoted using double or single quote marks (ASCII decimal 34 and 39 respectively). Single quote marks can be included within the attribute value when the value is delimited by double quote marks, and vice versa.

Note that some user agents require attribute minimisation for the following attributes: COMPACT, ISMAP, CHECKED, NOWRAP, NOSHADE and NOHREF. These user agents don’t accept syntax such as COMPACT=COMPACT or ISMAP=ISMAP although this is legitimate according to the HTML 3.2 DTD.

The SGML declaration and the DTD for use with HTML 3.2 are given in appendices. Further guidelines for parsing HTML are given in WD-html-lex.

---

The Structure of HTML documents

HTML 3.2 Documents start with a <!DOCTYPE> declaration followed by an HTML element containing a HEAD and then a BODY element:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<HTML>
<HEAD>
<TITLE>A study of population dynamics</TITLE>
... other head elements
</HEAD>
<BODY>
... document body
</BODY>
</HTML>

In practice, the HTML, HEAD and BODY start and end tags can be omitted from the markup as these can be inferred in all cases by parsers conforming to the HTML 3.2 DTD.

Every conforming HTML 3.2 document must start with the <!DOCTYPE> declaration that is needed to distinguish HTML 3.2 documents from other versions of HTML. The HTML specification is not concerned with storage entities. As a result, it is not required that the document type declaration reside in the same storage entity (i.e. file). A Web site may choose to dynamically prepend HTML files with the document type declaration if it is known that all such HTML files conform to the HTML 3.2 specification.

Every HTML 3.2 document must also include the descriptive title element. A minimal HTML 3.2 document thus looks like:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<TITLE>A study of population dynamics</TITLE>

Note: the word "Final" replaces "Draft" now that the HTML 3.2 specification has been ratified by the W3C member organizations.

---

The HEAD element

This contains the document head, but you can always omit both the start and end tags for HEAD. The contents of the document head is an unordered collection of the following elements:

• The TITLE element
• The STYLE element
• The SCRIPT element
• The ISINDEX element
• The BASE element
• The META element
• The LINK element

<!ENTITY % head.content "TITLE & ISINDEX? & BASE?">
<!ENTITY % head.misc "SCRIPT|STYLE|META|LINK">

<!ELEMENT HEAD O O  (%head.content) +(%head.misc)>

The %head.misc entity is used to allow the associated elements to occur multiple times at arbitrary positions within the HEAD. The following elements can be part of the document head:

TITLE defines the document title, and is always needed. ISINDEX for simple keyword searches, see PROMPT attribute. BASE defines base URL for resolving relative URLs. SCRIPT reserved for future use with scripting languages. STYLE reserved for future use with style sheets. META used to supply meta info as name/value pairs. LINK used to define relationships with other documents.

TITLE, SCRIPT and STYLE are containers and require both start and end tags. The other elements are not containers so that end tags are forbidden. Note that conforming browsers won’t render the contents of SCRIPT and STYLE elements.

TITLE

<!ELEMENT TITLE - -  (#PCDATA)* -(%head.misc)>

Every HTML 3.2 document must have exactly one TITLE element in the document’s HEAD. It provides an advisory title which can be displayed in a user agent’s window caption etc. The content model is PCDATA. As a result, character entities can be used for accented characters and to escape special characters such as & and <. Markup is not permitted in the content of a TITLE element.

Example TITLE element:

<TITLE>A study of population dynamics</TITLE>

STYLE and SCRIPT

<!ELEMENT STYLE  - - CDATA -- placeholder for style info -->
<!ELEMENT SCRIPT - - CDATA -- placeholder for script statements -->

These are place holders for the introduction of style sheets and client-side scripts in future versions of HTML. User agents should hide the contents of these elements.

These elements are defined with CDATA as the content type. As a result they may contain only SGML characters. All markup characters or delimiters are ignored and passed as data to the application, except for ETAGO ("</") delimiters followed immediately by a name character [a-zA-Z]. This means that the element’s end-tag (or that of an element in which it is nested) is recognized, while an error occurs if the ETAGO is invalid.

ISINDEX

<!ELEMENT ISINDEX - O EMPTY>
<!ATTLIST ISINDEX
prompt CDATA #IMPLIED -- prompt message -->

The ISINDEX element indicates that the user agent should provide a single line text input field for entering a query string. There are no restrictions on the number of characters that can be entered. The PROMPT attribute can be used to specify a prompt string for the input field, e.g.

<ISINDEX PROMPT="Search Phrase">

The semantics for ISINDEX are currently well defined only when the base URL for the enclosing document is an HTTP URL. Typically, when the user presses the enter (return) key, the query string is sent to the server identified by the base URL for this document. For example, if the query string entered is "ten green apples" and the base URL is:

http://www.acme.com/

then the query generated is:

http://www.acme.com/?ten+green+apples"

Note that space characters are mapped to "+" characters and that normal URL character escaping mechanisms apply. For further details see the HTTP specification.

Note in practice, the query string is resticted to Latin-1 as there is no current mechanism for the URL to specify a character set for the query.

BASE

<!ELEMENT BASE - O EMPTY>
<!ATTLIST BASE
href %URL  #REQUIRED
>

The BASE element gives the base URL for dereferencing relative URLs, using the rules given by the URL specification, e.g.

<BASE href="http://www.acme.com/intro.html">
...
<IMG SRC="../../icons/logo.gif">

The image is deferenced to

http://www.acme.com/icons/logo.gif

In the absence of a BASE element the document URL should be used. Note that this is not necessarily the same as the URL used to request the document, as the base URL may be overridden by an HTTP header accompanying the document.

META

<!ELEMENT META - O EMPTY    -- Generic Metainformation -->
<!ATTLIST META
http-equiv  NAME    #IMPLIED  -- HTTP response header name  --
name        NAME    #IMPLIED  -- metainformation name       --
content     CDATA   #REQUIRED -- associated information     --
>

The META element can be used to include name/value pairs describing properties of the document, such as author, expiry date, a list of key words etc. The NAME attribute specifies the property name while the CONTENT attribute specifies the property value, e.g.

<META NAME="Author" CONTENT="Dave Raggett">

The HTTP-EQUIV attribute can be used in place of the NAME attribute and has a special significance when documents are retrieved via the Hypertext Transfer Protocol (HTTP). HTTP servers may use the property name specified by the HTTP-EQUIV attribute to create an RFC 822 style header in the HTTP response. This can’t be used to set certain HTTP headers though, see the HTTP specification for details.

<META HTTP-EQUIV="Expires" CONTENT="Tue, 20 Aug 1996 14:25:27 GMT">

will result in the HTTP header:

Expires: Tue, 20 Aug 1996 14:25:27 GMT

This can be used by caches to determine when to fetch a fresh copy of the associated document.

LINK

LINK provides a media independent method for defining relationships with other documents and resources. LINK has been part of HTML since the very early days, although few browsers as yet take advantage of it (most still ignore LINK elements).

LINK elements can be used in principle:

1. for document specific navigation toolbars or menus
2. to control how collections of HTML files are rendered into printed documents
3. for linking associated resources such as style sheets and scripts
4. to provide alternative forms of the current document

<!ELEMENT LINK - O EMPTY>
<!ATTLIST LINK
href    %URL    #IMPLIED    -- URL for linked resource --
rel     CDATA   #IMPLIED    -- forward link types --
rev     CDATA   #IMPLIED    -- reverse link types --
title   CDATA   #IMPLIED    -- advisory title string --
>

href Specifies a URL designating the linked resource. rel The forward relationship also known as the "link type". It specifies a named relationship from the enclosing document to the resource specified by the HREF attribute. HTML link relationships are as yet unstandardized, although some conventions have been established. rev This defines a reverse relationship. A link from document A to document B with REV=relation expresses the same relationship as a link from B to A with REL=relation. REV=made is sometimes used to identify the document author, either the author’s email address with a mailto URL, or a link to the author’s home page. title An advisory title for the linked resource.

Here are some proposed relationship values:

rel=top The link references the top of a hierarchy, e.g. the first or cover page in a collection. rel=contents The link references a document serving as a table of contents. rel=index The link references a document providing an index for the current document. rel=glossary The link references a document providing a glossary of terms that are relevant to the current document. rel=copyright The link references a copyright statement for the current document. rel=next The link references the next document to visit in a guided tour. It can be used, for example, to preload the next page. rel=previous The link references the previous document in a guided tour. rel=help The link references a document offering help, e.g. describing the wider context and offering further links to relevant documents. This is aimed at reorienting users who have lost their way. rel=search The link references a page for searching material related to a collection of pages

Example LINK elements:

<LINK REL=Contents HREF=toc.html>
<LINK REL=Previous HREF=doc31.html>
<LINK REL=Next HREF=doc33.html>

<LINK REL=Chapter REV=Contents HREF=chapter2.html>

---

The BODY element

This contains the document body. Both start and end tags for BODY may be omitted. The body can contain a wide range of elements:

• Headings (H1 - H6)
• The ADDRESS element
• Block level Elements
• Text level elements

The key attributes are: BACKGROUND, BGCOLOR, TEXT, LINK, VLINK and ALINK. These can be used to set a repeating background image, plus background and foreground colors for normal text and hypertext links.

<!ENTITY % body.content "(%heading | %text | %block | ADDRESS)*">

<!ENTITY % color "CDATA" -- a color specification: #HHHHHH @@ details? -->

<!ENTITY % body-color-attrs "
bgcolor %color #IMPLIED
text %color #IMPLIED
link %color #IMPLIED
vlink %color #IMPLIED
alink %color #IMPLIED
">

<!ELEMENT BODY O O  %body.content>
<!ATTLIST BODY
background %URL #IMPLIED  -- texture tile for document background --
%body-color-attrs;  -- bgcolor, text, link, vlink, alink --
>

Example:

<body bgcolor=white text=black link=red vlink=maroon alink=fuchsia>

bgcolor Specifies the background color for the document body. See below for the syntax of color values. text Specifies the color used to stroke the document’s text. This is generally used when you have changed the background color with the BGCOLOR or BACKGROUND attributes. link Specifies the color used to stroke the text for unvisited hypertext links. vlink Specifies the color used to stroke the text for visited hypertext links. alink Specifies the highlight color used to stroke the text for hypertext links at the moment the user clicks on the link. background Specifies a URL for an image that will be used to tile the document background.

Colors are given in the sRGB color space as hexadecimal numbers (e.g. COLOR="#C0FFC0"), or as one of 16 widely understood color names. These colors were originally picked as being the standard 16 colors supported with the Windows VGA palette.

	Black = "#000000"		Green = "#008000"
	Silver = "#C0C0C0"		Lime = "#00FF00"
	Gray = "#808080"		Olive = "#808000"
	White = "#FFFFFF"		Yellow = "#FFFF00"
	Maroon = "#800000"		Navy = "#000080"
	Red = "#FF0000"		Blue = "#0000FF"
	Purple = "#800080"		Teal = "#008080"
	Fuchsia = "#FF00FF"		Aqua = "#00FFFF"

Block and Text level elements

Most elements that can appear in the document body fall into one of two groups: block level elements which cause paragraph breaks, and text level elements which don’t. Common block level elements include H1 to H6 (headers), P (paragraphs) LI (list items), and HR (horizontal rules). Common text level elements include EM, I, B and FONT (character emphasis), A (hypertext links), IMG and APPLET (embedded objects) and BR (line breaks). Note that block elements generally act as containers for text level and other block level elements (excluding headings and address elements), while text level elements can only contain other text level elements. The exact model depends on the element.

Headings

<!--
There are six levels of headers from H1 (the most important)
to H6 (the least important).
-->

<!ELEMENT ( %heading )  - -  (%text;)*>
<!ATTLIST ( %heading )
align  (left|center|right) #IMPLIED
>

H1, H2, H3, H4, H5 and H6 are used for document headings. You always need the start and end tags. H1 elements are more important than H2 elements and so on, so that H6 elements define the least important level of headings. More important headings are generally rendered in a larger font than less important ones. Use the optional ALIGN attribute to set the text alignment within a heading, e.g.

<H1 ALIGN=CENTER> ... centered heading ... </H1>

The default is left alignment, but this can be overridden by an enclosing DIV or CENTER element.

ADDRESS

<!ENTITY % address.content "((%text;) | P)*">

<!ELEMENT ADDRESS - - %address.content>

The ADDRESS element requires start and end tags, and specifies information such as authorship and contact details for the current document. User agents should render the content with paragraph-breaks before and after. Note that the content is restricted to paragraphs, plain text and text-like elements as defined by the %text entity.

Example:

<ADDRESS>
Newsletter editor<BR>
J.R. Brown<BR>
8723 Buena Vista, Smallville, CT 01234<BR>
Tel: +1 (123) 456 7890
</ADDRESS>

Block elements

P paragraphs The paragraph element requires a start tag, but the end tag can always be omitted. Use the ALIGN attribute to set the text alignment within a paragraph, e.g. <P ALIGN=RIGHT> UL unordered lists These require start and end tags, and contain one or more LI elements representing individual list items. OL ordered (i.e. numbered) lists These require start and end tags, and contain one or more LI elements representing individual list items. DL definition lists These require start and end tags and contain DT elements that give the terms, and DD elements that give corresponding definitions. PRE preformatted text Requires start and end tags. These elements are rendered with a monospaced font and preserve layout defined by whitespace and line break characters. DIV document divisions Requires start and end tags. It is used with the ALIGN attribute to set the text alignment of the block elements it contains. ALIGN can be one of LEFT, CENTER or RIGHT. CENTER text alignment Requires start and end tags. It is used to center text lines enclosed by the CENTER element. See DIV for a more general solution. BLOCKQUOTE quoted passage Requires start and end tags. It is used to enclose extended quotations and is typically rendered with indented margins. FORM fill-out forms Requires start and end tags. This element is used to define a fill-out form for processing by HTTP servers. The attributes are ACTION, METHOD and ENCTYPE. Form elements can’t be nested. ISINDEX primitive HTML forms Not a container, so the end tag is forbidden. This predates FORM and is used for simple kinds of forms which have a single text input field, implied by this element. A single ISINDEX can appear in the document head or body. HR horizontal rules Not a container, so the end tag is forbidden. attributes are ALIGN, NOSHADE, SIZE and WIDTH. TABLE can be nested Requires start and end tags. Each table starts with an optional CAPTION followed by one or more TR elements defining table rows. Each row has one or more cells defined by TH or TD elements. attributes for TABLE elements are WIDTH, BORDER, CELLSPACING and CELLPADDING.

---

Paragraphs

<!ELEMENT P     - O (%text)*>
<!ATTLIST P
align  (left|center|right) #IMPLIED
>

The P element is used to markup paragraphs. It is a container and requires a start tag. The end tag is optional as it can always be inferred by the parser. User agents should place paragraph breaks before and after P elements. The rendering is user agent dependent, but text is generally wrapped to fit the space available.

Example:

<P>This is the first paragraph.
<P>This is the second paragraph.

Paragraphs are usually rendered flush left with a ragged right margin. The ALIGN attribute can be used to explicitly specify the horizontal alignment:

align=leftThe paragraph is rendered flush left. align=centerThe paragraph is centered. align=rightThe paragraph is rendered flush right.

For example:

<p align=center>This is a centered paragraph.
<p align=right>and this is a flush right paragraph.

The default is left alignment, but this can be overridden by an enclosing DIV or CENTER element.

Lists

List items can contain block and text level items, including nested lists, although headings and address elements are excluded. This limitation is defined via the %flow entity.

Unordered Lists

<!ELEMENT UL - -  (LI)+>
<!ENTITY % ULStyle "disc|square|circle">

<!ATTLIST UL -- unordered lists --
type    (%ULStyle)   #IMPLIED   -- bullet style --
compact (compact)    #IMPLIED   -- reduced interitem spacing --
>

<!ELEMENT LI - O %flow -- list item -->
<!ATTLIST LI
type   (%LIStyle)    #IMPLIED   -- list item style --
>

Unordered lists take the form:

<UL>
<LI> ... first list item
<LI> ... second list item
...
</UL>

The UL element is used for unordered lists. Both start and end tags are always needed. The LI element is used for individual list items. The end tag for LI elements can always be omitted. Note that LI elements can contain nested lists. The COMPACT attribute can be used as a hint to the user agent to render lists in a more compact style.

The TYPE attribute can be used to set the bullet style on UL and LI elements. The permitted values are "disc", "square" or "circle". The default generally depends on the level of nesting for lists.

• with <li type=disc>
• with <li type=square>
• with <li type=circle>

This list was chosen to cater for the original bullet shapes used by Mosaic in 1993.

Ordered (i.e. numbered) Lists

<!ELEMENT OL - -  (LI)+>
<!ATTLIST OL -- ordered lists --
type      CDATA      #IMPLIED   -- numbering style --
start     NUMBER     #IMPLIED   -- starting sequence number --
compact  (compact)   #IMPLIED   -- reduced interitem spacing --
>

<!ELEMENT LI - O %flow -- list item -->
<!ATTLIST LI
type      CDATA      #IMPLIED   -- list item style --
value     NUMBER     #IMPLIED   -- set sequence number --
>

Ordered (i.e. numbered) lists take the form:

<OL>
<LI> ... first list item
<LI> ... second list item
...
</OL>

The OL START attribute can be used to initialize the sequence number (by default it is initialized to 1). You can set it later on with the VALUE attribute on LI elements. Both of these attributes expect integer values. You can’t indicate that numbering should be continued from a previous list, or to skip missing values without giving an explicit number.

The COMPACT attribute can be used as a hint to the user agent to render lists in a more compact style. The OL TYPE attribute allows you to set the numbering style for list items:

Type	Numbering style
1	Arabic numbers	1, 2, 3, ...
a	lower alpha	a, b, c, ...
A	upper alpha	A, B, C, ...
i	lower roman	i, ii, iii, ...
I	upper roman	I, II, III, ...

Definition Lists

<!-- definition lists - DT for term, DD for its definition -->

<!ELEMENT DL    - -  (DT|DD)+>
<!ATTLIST DL
compact (compact) #IMPLIED -- more compact style --
>

<!ELEMENT DT - O  (%text)*>
<!ELEMENT DD - O  %flow;>

Definition lists take the form:

<DL>
<DT> term name
<DD> term definition
...
</DL>

DT elements can only act as containers for text level elements, while DD elements can hold block level elements as well, excluding headings and address elements.

For example:

<DL>
<DT>Term 1<dd>This is the definition of the first term.
<DT>Term 2<dd>This is the definition of the second term.
</DL>

which could be rendered as:

Term 1This is the definition of the first term. Term 2This is the definition of the second term.

The COMPACT attribute can be used with the DL element as a hint to the user agent to render lists in a more compact style.

DIR and MENU

<!ELEMENT (DIR|MENU) - -  (LI)+ -(%block)>
<!ATTLIST (DIR|MENU)
compact (compact) #IMPLIED
>

These elements have been part of HTML from the early days. They are intended for unordered lists similar to UL elements. User agents are recommended to render DIR elements as multicolumn directory lists, and MENU elements as single column menu lists. In practice, Mosaic and most other user agents have ignored this advice and instead render DIR and MENU in an identical way to UL elements.

Preformatted Text

<!ELEMENT PRE - - (%text)* -(%pre.exclusion)>
<!ATTLIST PRE
width NUMBER #implied
>

The PRE element can be used to include preformatted text. User agents render this in a fixed pitch font, preserving spacing associated with white space characters such as space and newline characters. Automatic word-wrap should be disabled within PRE elements.

Note that the SGML standard requires that the parser remove a newline immediately following the start tag or immediately preceding the end tag.

PRE has the same content model as paragraphs, excluding images and elements that produce changes in font size, e.g. IMG, BIG, SMALL, SUB, SUP and FONT.

A few user agents support the WIDTH attribute. It provides a hint to the user agent of the required width in characters. The user agent can use this to select an appropriate font size or to indent the content appropriately.

Here is an example of a PRE element; a verse from Shelley (To a Skylark):

<PRE>
Higher still and higher
From the earth thou springest
Like a cloud of fire;
The blue deep thou wingest,
And singing still dost soar, and soaring ever singest.
</PRE>

which is rendered as:

Higher still and higher
From the earth thou springest
Like a cloud of fire;
The blue deep thou wingest,
And singing still dost soar, and soaring ever singest.

The horizontal tab character (encoded in Unicode, US ASCII and ISO 8859-1 as decimal 9) should be interpreted as the smallest non-zero number of spaces which will leave the number of characters so far on the line as a multiple of 8. Its use is strongly discouraged since it is common practice when editing to set the tab-spacing to other values, leading to misaligned documents.

XMP, LISTING and PLAINTEXT

<![ %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>
<!ELEMENT PLAINTEXT - O %literal>

]]>

These are obsolete tags for preformatted text that predate the introduction of PRE. User agents may support these for backwards compatibility. Authors should avoid using them in new documents!

DIV and CENTER

<!ELEMENT DIV - - %body.content>
<!ATTLIST DIV
align   (left|center|right) #IMPLIED -- alignment of following text --
>

<!-- CENTER is a shorthand for DIV with ALIGN=CENTER -->
<!ELEMENT center - - %body.content>

DIV elements can be used to structure HTML documents as a hierarchy of divisions. The ALIGN attribute can be used to set the default horizontal alignment for elements within the content of the DIV element. Its value is restricted to LEFT, CENTER or RIGHT, and is defined in the same way as for the paragraph element <P>.

Note that because DIV is a block-like element it will terminate an open P element. Other than this, user agents are not expected to render paragraph breaks before and after DIV elements. CENTER is directly equivalent to DIV with ALIGN=CENTER. Both DIV and CENTER require start and end tags.

CENTER was introduced by Netscape before they added support for the HTML 3.0 DIV element. It is retained in HTML 3.2 on account of its widespread deployment.

BLOCKQUOTE

<!ELEMENT BLOCKQUOTE - - %body.content>

This is used to enclose block quotations from other works. Both the start and end tags are required. It is often rendered indented, e.g.

They went in single file, running like hounds on a strong scent, and an eager light was in their eyes. Nearly due west the broad swath of the marching Orcs tramped its ugly slot; the sweet grass of Rohan had been bruised and blackened as they passed.

from "The Two Towers" by J.R.R. Tolkien.

FORM

<!ENTITY % HTTP-Method "GET | POST"
-- as per HTTP specification
-->

<!ELEMENT FORM - - %body.content -(FORM)>
<!ATTLIST FORM
action %URL #IMPLIED  -- server-side form handler --
method (%HTTP-Method) GET -- see HTTP specification --
enctype %Content-Type; "application/x-www-form-urlencoded"
>

This is used to define an HTML form, and you can have more than one form in the same document. Both the start and end tags are required. For very simple forms, you can also use the ISINDEX element. Forms can contain a wide range of HTML markup including several kinds of form fields such as single and multi-line text fields, radio button groups, checkboxes, and menus.

action This specifies a URL which is either used to post forms via email, e.g. action="mailto:foo@bar.com", or used to invoke a server-side forms handler via HTTP, e.g. action="http://www.acme.com/cgi-bin/register.pl" method When the action attribute specifies an HTTP server, the method attribute determines which HTTP method will be used to send the form’s contents to the server. It can be either GET or POST, and defaults to GET. enctype This determines the mechanism used to encode the form’s contents. It defaults to application/x-www-form-urlencoded.

Further details on handling forms are given in RFC 1867.

HR - horizontal rules

Horizontal rules may be used to indicate a change in topic. In a speech based user agent, the rule could be rendered as a pause.

<!ELEMENT HR    - O EMPTY>
<!ATTLIST HR
align (left|right|center) #IMPLIED
noshade (noshade) #IMPLIED
size  %Pixels #IMPLIED
width %Length #IMPLIED
>

HR elements are not containers so the end tag is forbidden. The attributes are: ALIGN, NOSHADE, SIZE and WIDTH.

align This determines whether the rule is placed at the left, center or right of the space between the current left and right margins for align=left, align=center or align=right respectively. By default, the rule is centered. noshade This attribute requests the user agent to render the rule in a solid color rather than as the traditional two colour "groove". size This can be used to set the height of the rule in pixels. width This can be used to set the width of the rule in pixels (e.g. width=100) or as the percentage between the current left and right margins (e.g. width="50%"). The default is 100%.

Tables

HTML 3.2 includes a widely deployed subset of the specification given in RFC 1942 and can be used to markup tabular material or for layout purposes. Note that the latter role typically causes problems when rending to speech or to text only user agents.

<!-- horizontal placement of table relative to window -->
<!ENTITY % Where "(left|center|right)">

<!-- horizontal alignment attributes for cell contents -->
<!ENTITY % cell.halign
"align  (left|center|right) #IMPLIED"
>

<!-- vertical alignment attributes for cell contents -->
<!ENTITY % cell.valign
"valign  (top|middle|bottom)  #IMPLIED"
>

<!ELEMENT table - - (caption?, tr+)>
<!ELEMENT tr - O (th|td)*>
<!ELEMENT (th|td) - O %body.content>

<!ATTLIST table                       -- table element --
align     %Where;   #IMPLIED  -- table position relative to window --
width     %Length   #IMPLIED  -- table width relative to window --
border    %Pixels   #IMPLIED  -- controls frame width around table --
cellspacing %Pixels #IMPLIED  -- spacing between cells --
cellpadding %Pixels #IMPLIED  -- spacing within cells --
>

<!ELEMENT CAPTION - - (%text;)* -- table or figure caption -->
<!ATTLIST CAPTION
align (top|bottom) #IMPLIED
>

<!ATTLIST tr                       -- table row --
%cell.halign;              -- horizontal alignment in cells --
%cell.valign;              -- vertical alignment in cells --
>

<!ATTLIST (th|td)                  -- header or data cell --
nowrap (nowrap)  #IMPLIED  -- suppress word wrap --
rowspan NUMBER   1         -- number of rows spanned by cell --
colspan NUMBER   1         -- number of cols spanned by cell --
%cell.halign;              -- horizontal alignment in cells --
%cell.valign;              -- vertical alignment in cells --
width   %Pixels  #IMPLIED  -- suggested width for cell --
height  %Pixels  #IMPLIED  -- suggested height for cell --
>

Tables take the general form:

<TABLE BORDER=3 CELLSPACING=2 CELLPADDING=2 WIDTH="80%">
<CAPTION> ... table caption ... </CAPTION>
<TR><TD> first cell <TD> second cell
<TR> ...
...
</TABLE>

The attributes on TABLE are all optional. By default, the table is rendered without a surrounding border. The table is generally sized automatically to fit the contents, but you can also set the table width using the WIDTH attribute. BORDER, CELLSPACING and CELLPADDING provide further control over the table’s appearence. Captions are rendered at the top or bottom of the table depending on the ALIGN attribute.

Each table row is contained in a TR element, although the end tag can always be omitted. Table cells are defined by TD elements for data and TH elements for headers. Like TR, these are containers and can be given without trailing end tags. TH and TD support several attributes: ALIGN and VALIGN for aligning cell content, ROWSPAN and COLSPAN for cells which span more than one row or column. A cell can contain a wide variety of other block and text level elements including form fields and other tables.

The TABLE element always requires both start and end tags. It supports the following attributes:

align This takes one of the case insensitive values: LEFT, CENTER or RIGHT. It specifies the horizontal placement of the table relative to the current left and right margins. It defaults to left alignment, but this can be overridden by an enclosing DIV or CENTER element. width In the absence of this attribute the table width is automatically determined from the table contents. You can use the WIDTH attribute to set the table width to a fixed value in pixels (e.g. WIDTH=212) or as a percentage of the space between the current left and right margins (e.g. WIDTH="80%"). border This attribute can be used to specify the width of the outer border around the table to a given number of pixels (e.g. BORDER=4). The value can be set to zero to suppress the border altogether. In the absence of this attribute the border should be suppressed. Note that some browsers also accept <TABLE BORDER> with the same semantics as BORDER=1. cellspacing In traditional desktop publishing software, adjacent table cells share a common border. This is not the case in HTML. Each cell is given its own border which is separated from the borders around neighboring cells. This separation can be set in pixels using the CELLSPACING attribute, (e.g. CELLSPACING=10). The same value also determines the separation between the table border and the borders of the outermost cells. cellpadding This sets the padding in pixels between the border around each cell and the cell’s contents.

The CAPTION element has one attribute ALIGN which can be either ALIGN=TOP or ALIGN=BOTTOM. This can be used to force the caption to be placed above the top or below the bottom of the table respectively. Most user agents default to placing the caption above the table. CAPTION always requires both start and end tags. Captions are limited to plain text and text-level elements as defined by the %text entity. Block level elements are not permitted.

The TR or table row element requires a start tag, but the end tag can always be left out. TR acts as a container for table cells. It has two attributes:

align Sets the default horizontal alignment of cell contents. It takes one of the case insensitive values: LEFT, CENTER or RIGHT and plays the same role as the ALIGN attribute on paragraph elements. valign This can be used to set the default vertical alignment of cell contents within each cell. It takes one of the case insensitive values: TOP, MIDDLE or BOTTOM to position the cell contents at the top, middle or bottom of the cell respectively.

There are two elements for defining table cells. TH is used for header cells and TD for data cells. This distinction allows user agents to render header and data cells in different fonts, and enables speech based browsers to do a better job. The start tags for TH and TD are always needed but the end tags can be left out. Table cells can have the following attributes:

nowrap The presence of this attribute disables automatic word wrap within the contents of this cell (e.g. <TD NOWRAP>). This is equivalent to using the   entity for non-breaking spaces within the content of the cell. rowspan This takes a positive integer value specifying the number of rows spanned by this cell. It defaults to one. colspan This takes a positive integer value specifying the number of columns spanned by this cell. It defaults to one. align Specifies the default horizontal alignment of cell contents, and overrides the ALIGN attribute on the table row. It takes the same values: LEFT, CENTER and RIGHT. If you don’t specify an ALIGN attribute value on the cell, the default is left alignment for <td> and center alignment for <th> although you can override this with an ALIGN attribute on the TR element. valign Specifies the default vertical alignment of cell contents, overriding the VALIGN attribute on the table row. It takes the same values: TOP, MIDDLE and BOTTOM. If you don’t specify a VALIGN attribute value on the cell, the default is middle although you can override this with a VALIGN attribute on the TR element. width Specifies the suggested width for a cell content in pixels excluding the cell padding. This value will normally be used except when it conflicts with the width requirements for other cells in the same column. height Specifies the suggested height for a cell content in pixels excluding the cell padding. This value will normally be used except when it conflicts with the height requirements for other cells in the same row.

Tables are commonly rendered in bas-relief, raised up with the outer border as a bevel, and individual cells inset into this raised surface. Borders around individual cells are only drawn if the cell has explicit content. White space doesn’t count for this purpose with the exception of  .

The algorithms used to automatically size tables should take into account the minimum and maximum width requirements for each cell. This is used to determine the minimum and maximum width requirements for each column and hence for the table itself.

Cells spanning more than one column contribute to the widths of each of the columns spanned. One approach is to evenly apportion the cell’s minimum and maximum width between these columns, another is to weight the apportioning according to the contributions from cells that don’t span multiple columns.

For some user agents it may be necessary or desirable to break text lines within words. In such cases a visual indication that this has occurred is advised.

The minimum and maximum width of nested tables contribute to the minimum and maximum width of the cell in which they occur. Once the width requirements are known for the top level table, the column widths for that table can be assigned. This allows the widths of nested tables to be assigned and hence in turn the column widths of such tables. If practical, all columns should be assigned at least their minimum widths. It is suggested that any surplus space is then shared out proportional to the difference between the minimum and maximum width requirements of each column.

Note that pixel values for width and height refer to screen pixels, and should be multiplied by an appropriate factor when rendering to very high resolution devices such as laser printers. For instance if a user agent has a display with 75 pixels per inch and is rendering to a laser printer with 600 dots per inch, then the pixel values given in HTML attributes should be multiplied by a factor of 8.

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Text level elements

These don’t cause paragraph breaks. Text level elements that define character styles can generally be nested. They can contain other text level elements but not block level elements.

• Font style elements
• Phrase elements
• Form Fields
• The A (anchor) element
• IMG - inline images
• APPLET (Java Applets)
• FONT elements
• BASEFONT elements
• BR - line breaks
• MAP - client-side image maps

Font style elements

These all require start and end tags, e.g.

This has some <B>bold text</B>.

Text level elements must be properly nested - the following is in error:

This has some <B>bold and <I></B>italic text</I>.

User agents should do their best to respect nested emphasis, e.g.

This has some <B>bold and <I>italic text</I></B>.

Where the available fonts are restricted or for speech output, alternative means should be used for rendering differences in emphasis.

TT teletype or monospaced text I italic text style B bold text style U underlined text style STRIKE strike-through text style BIG places text in a large font SMALL places text in a small font SUB places text in subscript style SUP places text in superscript style

Note: future revisions to HTML may be phase out STRIKE in favor of the more concise "S" tag from HTML 3.0.

Phrase Elements

These all require start and end tags, e.g.

This has some <EM>emphasized text</EM>.

EM basic emphasis typically rendered in an italic font STRONG strong emphasis typically rendered in a bold font DFN defining instance of the enclosed term CODE used for extracts from program code SAMP used for sample output from programs, and scripts etc. KBD used for text to be typed by the user VAR used for variables or arguments to commands CITE used for citations or references to other sources

Form fields

INPUT, SELECT and TEXTAREA are only allowed within FORM elements. INPUT can be used for a variety of form fields including single line text fields, password fields, checkboxes, radio buttons, submit and reset buttons, hidden fields, file upload, and image buttons. SELECT elements are used for single or multiple choice menus. TEXTAREA elements are used to define multi-line text fields. The content of the element is used to initialize the field.

INPUT text fields, radio buttons, check boxes, ...

INPUT elements are not containers and so the end tag is forbidden.

<!ENTITY % IAlign "(top|middle|bottom|left|right)">

<!ENTITY % InputType
"(TEXT | PASSWORD | CHECKBOX | RADIO | SUBMIT
| RESET | FILE | HIDDEN | IMAGE)">

<!ELEMENT INPUT - O EMPTY>
<!ATTLIST INPUT
type %InputType TEXT     -- what kind of widget is needed --
name  CDATA #IMPLIED     -- required for all but submit and reset --
value CDATA #IMPLIED     -- required for radio and checkboxes --
checked (checked) #IMPLIED -- for radio buttons and check boxes --
size CDATA  #IMPLIED     -- specific to each type of field --
maxlength NUMBER #IMPLIED
src   %URL  #IMPLIED     -- for fields with background images --
align %IAlign #IMPLIED   -- vertical or horizontal alignment --
>

type Used to set the type of input field:

type=text (the default) A single line text field whose visible size can be set using the size attribute, e.g. size=40 for a 40 character wide field. Users should be able to type more than this limit though with the text scrolling through the field to keep the input cursor in view. You can enforce an upper limit on the number of characters that can be entered with the maxlength attribute. The name attribute is used to name the field, while the value attribute can be used to initialize the text string shown in the field when the document is first loaded.

<input type=text size=40 name=user value="your name">

type=password This is like type=text, but echoes characters using a character like * to hide the text from prying eyes when entering passwords. You can use size and maxlength attributes to control the visible and maximum length exactly as per regular text fields.

<input type=password size=12 name=pw>

type=checkbox Used for simple Boolean attributes, or for attributes that can take multiple values at the same time. The latter is represented by several checkbox fields with the same name and a different value attribute. Each checked checkbox generates a separate name/value pair in the submitted data, even if this results in duplicate names. Use the checked attribute to initialize the checkbox to its checked state.

<input type=checkbox checked name=uscitizen value=yes>

type=radio Used for attributes which can take a single value from a set of alternatives. Each radio button field in the group should be given the same name. Radio buttons require an explicit value attribute. Only the checked radio button in the group generates a name/value pair in the submitted data. One radio button in each group should be initially checked using the checked attribute.

<input type=radio name=age value="0-12">
<input type=radio name=age value="13-17">
<input type=radio name=age value="18-25">
<input type=radio name=age value="26-35" checked>
<input type=radio name=age value="36-">

type=submit This defines a button that users can click to submit the form’s con