REC-html32

                      HTML 3.2 Reference Specification

                       W3C Recommendation 14-Jan-1997

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. It is a
stable document and may be used as reference material or cited as a
normative reference from another document. W3C's role in making the
Recommendation is to draw attention to the specification and to promote its
widespread deployment. This enhances the functionality and interoperability
of the Web.

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

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).
  ------------------------------------------------------------------------

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 ...

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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. &eacute;. The & character can be included
in its own right using the named character entity &amp;.

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:

  a. for document specific navigation toolbars or menus
  b. to control how collections of HTML files are rendered into printed
     documents
  c. for linking associated resources such as style sheets and scripts
  d. 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.

                         Color names and sRGB values

         [Image] Black = "#000000"      [Image] Green = "#008000"

         [Image] Silver = "#C0C0C0"     [Image] Lime = "#00FF00"

         [Image] Gray = "#808080"       [Image] Olive = "#808000"

         [Image] White = "#FFFFFF"      [Image] Yellow = "#FFFF00"

         [Image] Maroon = "#800000"     [Image] Navy = "#000080"

         [Image] Red = "#FF0000"        [Image] Blue = "#0000FF"

         [Image] Purple = "#800080"     [Image] Teal = "#008080"

         [Image] Fuchsia = "#FF00FF"    [Image] 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=left
     The paragraph is rendered flush left.
align=center
     The paragraph is centered.
align=right
     The 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>
   o 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 1
     This is the definition of the first term.
Term 2
     This 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 &nbsp; 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 &nbsp;.

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.
  ------------------------------------------------------------------------

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
          contents to the server. The button's label is set from the value
          attribute. If the name attribute is given then the submit button's
          name/value pair will be included in the submitted data. You can
          include several submit buttons in the form. See type=image for
          graphical submit buttons.

              <input type=submit value="Party on ...">

     type=image
          This is used for graphical submit buttons rendered by an image
          rather than a text string. The URL for the image is specified with
          the src attribute. The image alignment can be specified with the
          align attribute. In this respect, graphical submit buttons are
          treated identically to IMG elements, so you can set align to left,
          right, top, middle or bottom. The x and y values of the location
          clicked are passed to the server: In the submitted data, image
          fields are included as two name/value pairs. The names are derived
          by taking the name of the field and appending ".x" for the x
          value, and ".y" for the y value.

          <p>Now choose a point on the map:

              <input type=image name=point src="map.gif">

          Note: image fields typically cause problems for text-only and
          speech-based user agents!

     type=reset
          This defines a button that users can click to reset form fields to
          their initial state when the document was first loaded. You can
          set the label by providing a value attribute. Reset buttons are
          never sent as part of the form's contents.

              <input type=reset value="Start over ...">

     type=file
          This provides a means for users to attach a file to the form's
          contents. It is generally rendered by text field and an associated
          button which when clicked invokes a file browser to select a file
          name. The file name can also be entered directly in the text
          field. Just like type=text you can use the size attribute to set
          the visible width of this field in average character widths. You
          can set an upper limit to the length of file names using the
          maxlength attribute. Some user agents support the ability to
          restrict the kinds of files to those matching a comma separated
          list of MIME content types given with the ACCEPT attribute e.g.
          accept="image/*" restricts files to images. Further information
          can be found in RFC 1867.

              <input type=file name=photo size=20 accept="image/*">

     type=hidden
          These fields should not be rendered and provide a means for
          servers to store state information with a form. This will be
          passed back to the server when the form is submitted, using the
          name/value pair defined by the corresponding attributes. This is a
          work around for the statelessness of HTTP. Another approach is to
          use HTTP "Cookies".

              <input type=hidden name=customerid value="c2415-345-8563">

name
     Used to define the property name that will be used to identify this
     field's content when it is submitted to the server.
value
     Used to initialize the field, or to provide a textual label for submit
     and reset buttons.
checked
     The presence of this attribute is used to initialize checkboxes and
     radio buttons to their checked state.
size
     Used to set the visible size of text fields to a given number of
     average character widths, e.g. size=20
maxlength
     Sets the maximum number of characters permitted in a text field.
src
     Specifies a URL for the image to use with a graphical submit button.
align
     Used to specify image alignment for graphical submit buttons. It is
     defined just like the IMG align attribute and takes one of the values:
     top, middle, bottom, left or right, defaulting to bottom.

SELECT menus

<!ELEMENT SELECT - - (OPTION+)>
<!ATTLIST SELECT
        name CDATA #REQUIRED
        size NUMBER #IMPLIED
        multiple (multiple) #IMPLIED
        >

<!ELEMENT OPTION - O (#PCDATA)*>
<!ATTLIST OPTION
        selected (selected) #IMPLIED
        value  CDATA  #IMPLIED -- defaults to element content --
        >

SELECT is used to define select one from many or many from many menus.
SELECT elements require start and end tags and contain one or more OPTION
elements that define menu items. One from many menus are generally rendered
as drop-down menus while many from many menus are generally shown as list
boxes.

Example:

    <SELECT NAME="flavor">
    <OPTION VALUE=a>Vanilla
    <OPTION VALUE=b>Strawberry
    <OPTION VALUE=c>Rum and Raisin
    <OPTION VALUE=d>Peach and Orange
    </SELECT>

SELECT attributes:

name
     This specifies a property name that is used to identify the menu choice
     when the form is submitted to the server. Each selected option results
     in a property name/value pair being included as part of the form's
     contents.
size
     This sets the number of visible choices for many from many menus.
multiple
     The presence of this attribute signifies that the users can make
     multiple selections. By default only one selection is allowed.

OPTION attributes:

selected
     When this attribute is present, the option is selected when the
     document is initially loaded. It is an error for more than one option
     to be so selected for one from many menus.
value
     Specifies the property value to be used when submitting the form's
     content. This is combined with the property name as given by the name
     attribute of the parent SELECT element.

TEXTAREA multi-line text fields

<!-- Multi-line text input field. -->

<!ELEMENT TEXTAREA - - (#PCDATA)*>
<!ATTLIST TEXTAREA
        name CDATA #REQUIRED
        rows NUMBER #REQUIRED
        cols NUMBER #REQUIRED
        >

TEXTAREA elements require start and end tags. The content of the element is
restricted to text and character entities. It is used to initialize the text
that is shown when the document is first loaded.

Example:

    <TEXTAREA NAME=address ROWS=4 COLS=40>
    Your address here ...
    </TEXTAREA>

It is recommended that user agents canonicalize line endings to CR, LF
(ASCII decimal 13, 10) when submitting the field's contents. The character
set for submitted data should be ISO Latin-1, unless the server has
previously indicated that it can support alternative character sets.

name
     This specifies a property name that is used to identify the textarea
     field when the form is submitted to the server.
rows
     Specifies the number of visible text lines. Users should be able to
     enter more lines that this, so user agents should provide some means to
     scroll through the contents of the textarea field when the contents
     extend beyond the visible area.
cols
     Specifies the visible width in average character widths. Users should
     be able to enter longer lines that this, so user agents should provide
     some means to scroll through the contents of the textarea field when
     the contents extend beyond the visible area. User agents may wrap
     visible text lines to keep long lines visible without the need for
     scrolling.

Special Text level Elements

A (Anchor), IMG, APPLET, FONT, BASEFONT, BR and MAP.

The A (anchor) element

<!ELEMENT A - - (%text)* -(A)>
<!ATTLIST A
        name    CDATA   #IMPLIED    -- named link end --
        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 --
        >

Anchors can't be nested and always require start and end tags. They are used
to define hypertext links and also to define named locations for use as
targets for hypertext links, e.g.

   The way to <a href="hands-on.html">happiness</a>.

and also to define named locations for use as targets for hypertext links,
e.g.

   <h2><a name=mit>545 Tech Square - Hacker's Paradise</a></h2>

name
     This should be a string defining unique name for the scope of the
     current HTML document. NAME is used to associate a name with this part
     of a document for use with URLs that target a named section of a
     document.
href
     Specifies a URL acting as a network address for the linked resource.
     This could be another HTML document, a PDF file or an image etc.
rel
     The forward relationship also known as the "link type". It can be used
     to determine to how to deal with the linked resource when printing out
     a collection of linked resources.
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.

IMG - inline images

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

<!ELEMENT IMG    - O EMPTY --  Embedded image -->
<!ATTLIST IMG
        src     %URL     #REQUIRED  -- URL of image to embed --
        alt     CDATA    #IMPLIED   -- for display in place of image --
        align   %IAlign  #IMPLIED   -- vertical or horizontal alignment --
        height  %Pixels  #IMPLIED   -- suggested height in pixels --
        width   %Pixels  #IMPLIED   -- suggested width in pixels --
        border  %Pixels  #IMPLIED   -- suggested link border width --
        hspace  %Pixels  #IMPLIED   -- suggested horizontal gutter --
        vspace  %Pixels  #IMPLIED   -- suggested vertical gutter --
        usemap  %URL     #IMPLIED   -- use client-side image map --
        ismap   (ismap)  #IMPLIED   -- use server image map --
        >

Used to insert images. IMG is an empty element and so the end tag is
forbidden. Images can be positioned vertically relative to the current
textline or floated to the left or right. See BR with the CLEAR attribute
for control over textflow.

e.g.  <IMG SRC="canyon.gif" ALT="Grand Canyon">

IMG elements support the following attributes:

src
     This attribute is required for every IMG element. It specifies a URL
     for the image resource, for instance a GIF, JPEG or PNG image file.
alt
     This is used to provide a text description of the image and is vital
     for interoperability with speech-based and text only user agents.
align
     This specifies how the image is positioned relative to the current
     textline in which it occurs:

     align=top
          positions the top of the image with the top of the current text
          line. User agents vary in how they interpret this. Some only take
          into account what has occurred on the text line prior to the IMG
          element and ignore what happens after it.
     align=middle
          aligns the middle of the image with the baseline for the current
          textline.
     align=bottom
          is the default and aligns the bottom of the image with the
          baseline.
     align=left
          floats the image to the current left margin, temporarily changing
          this margin, so that subsequent text is flowed along the image's
          righthand side. The rendering depends on whether there is any left
          aligned text or images that appear earlier than the current image
          in the markup. Such text (but not images) generally forces left
          aligned images to wrap to a new line, with the subsequent text
          continuing on the former line.
     align=right
          floats the image to the current right margin, temporarily changing
          this margin, so that subsequent text is flowed along the image's
          lefthand side. The rendering depends on whether there is any right
          aligned text or images that appear earlier than the current image
          in the markup. Such text (but not images) generally forces right
          aligned images to wrap to a new line, with the subsequent text
          continuing on the former line.

     Note that some browsers introduce spurious spacing with multiple left
     or right aligned images. As a result authors can't depend on this being
     the same for browsers from different vendors. See BR for ways to
     control text flow.
width
     Specifies the intended width of the image in pixels. When given
     together with the height, this allows user agents to reserve screen
     space for the image before the image data has arrived over the network.
height
     Specifies the intended height of the image in pixels. When given
     together with the width, this allows user agents to reserve screen
     space for the image before the image data has arrived over the network.
border
     When the IMG element appears as part of a hypertext link, the user
     agent will generally indicate this by drawing a colored border
     (typically blue) around the image. This attribute can be used to set
     the width of this border in pixels. Use border=0 to suppress the border
     altogether. User agents are recommended to provide additional cues that
     the image is clickable, e.g. by changing the mouse pointer.
hspace
     This can be used to provide white space to the immediate left and right
     of the image. The HSPACE attribute sets the width of this white space
     in pixels. By default HSPACE is a small non-zero number.
vspace
     This can be used to provide white space above and below the image The
     VSPACE attribute sets the height of this white space in pixels. By
     default VSPACE is a small non-zero number.
usemap
     This can be used to give a URL fragment identifier for a client-side
     image map defined with the MAP element.
ismap
     When the IMG element is part of a hypertext link, and the user clicks
     on the image, the ISMAP attribute causes the location to be passed to
     the server. This mechanism causes problems for text-only and
     speech-based user agents. Whenever its possible to do so use the MAP
     element instead.

Here is an example of how you use ISMAP:

<a href="/cgibin/navbar.map"><img src=navbar.gif ismap border=0></a>

The location clicked is passed to the server as follows. The user agent
derives a new URL from the URL specified by the HREF attribute by appending
`?' the x coordinate `,' and the y coordinate of the location in pixels. The
link is then followed using the new URL. For instance, if the user clicked
at at the location x=10, y=27 then the derived URL will be:
"/cgibin/navbar.map?10,27". It is generally a good idea to suppress the
border and use graphical idioms to indicate that the image is clickable.

Note that pixel values 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.

APPLET (Java Applets)

<!ELEMENT APPLET - - (PARAM | %text)*>
<!ATTLIST APPLET
        codebase %URL     #IMPLIED   -- code base --
        code     CDATA    #REQUIRED  -- class file --
        alt      CDATA    #IMPLIED   -- for display in place of applet --
        name     CDATA    #IMPLIED   -- applet name --
        width    %Pixels  #REQUIRED  -- suggested width in pixels --
        height   %Pixels  #REQUIRED  -- suggested height in pixels --
        align    %IAlign  #IMPLIED   -- vertical or horizontal alignment --
        hspace   %Pixels  #IMPLIED   -- suggested horizontal gutter --
        vspace   %Pixels  #IMPLIED   -- suggested vertical gutter --
        >

<!ELEMENT PARAM - O EMPTY>
<!ATTLIST PARAM
    name    NMTOKEN   #REQUIRED  -- The name of the parameter --
    value   CDATA     #IMPLIED   -- The value of the parameter --
    >

Requires start and end tags. This element is supported by all Java enabled
browsers. It allows you to embed a Java applet into HTML documents. APPLET
uses associated PARAM elements to pass parameters to the applet. Following
the PARAM elements, the content of APPLET elements should be used to provide
an alternative to the applet for user agents that don't support Java. It is
restricted to text-level markup as defined by the %text entity in the DTD.
Java-compatible browsers ignore this extra HTML code. You can use it to show
a snapshot of the applet running, with text explaining what the applet does.
Other possibilities for this area are a link to a page that is more useful
for the Java-ignorant browser, or text that taunts the user for not having a
Java-compatible browser.

Here is a simple example of a Java applet:

    <applet code="Bubbles.class" width=500 height=500>
    Java applet that draws animated bubbles.
    </applet>

Here is another one using a PARAM element:

    <applet code="AudioItem" width=15 height=15>
    <param name=snd value="Hello.au|Welcome.au">
    Java applet that plays a welcoming sound.
    </applet>

codebase = codebaseURL
     This optional attribute specifies the base URL of the applet -- the
     directory or folder that contains the applet's code. If this attribute
     is not specified, then the document's URL is used.

code = appletFile
     This required attribute gives the name of the file that contains the
     applet's compiled Applet subclass. This file is relative to the base
     URL of the applet. It cannot be absolute.

alt = alternateText
     This optional attribute specifies any text that should be displayed if
     the browser understands the APPLET tag but can't run Java applets.

name = appletInstanceName
     This optional attribute specifies a name for the applet instance, which
     makes it possible for applets on the same page to find (and communicate
     with) each other.

width = pixels
height = pixels
     These required attributes give the initial width and height (in pixels)
     of the applet display area, not counting any windows or dialogs that
     the applet brings up.

align = alignment
     This attribute specifies the alignment of the applet. This attribute is
     defined in exactly the same way as the IMG element. The permitted
     values are: top, middle, bottom, left and right. The default is bottom.

vspace = pixels
hspace = pixels
     These optional attributes specify the number of pixels above and below
     the applet (VSPACE) and on each side of the applet (HSPACE). They're
     treated the same way as the IMG element's VSPACE and HSPACE attributes.

The PARAM element is used to pass named parameters to applet:

   <PARAM NAME = appletParameter VALUE = value>

PARAM elements are the only way to specify applet-specific parameters.
Applets read user-specified values for parameters with the getParameter()
method.

name = applet parameter name
value = parameter value

SGML character entities such as &eacute; and &#185; are expanded before the
parameter value is passed to the applet. To include an & character use
&amp;.

Note: PARAM elements should be placed at the start of the content for the
APPLET element. This is not specified as part of the DTD due to
technicalities with SGML mixed content models.

FONT

<!ELEMENT FONT - - (%text)*     -- local change to font -->
<!ATTLIST FONT
    size    CDATA   #IMPLIED    -- [+]nn e.g. size="+1", size=4 --
    color   CDATA   #IMPLIED    -- #RRGGBB in hex, e.g. red: color="#FF0000" --
    >

Requires start and end tags. This allows you to change the font size and/or
color for the enclosed text. The attributes are: SIZE and COLOR. Font sizes
are given in terms of a scalar range defined by the user agent with no
direct mapping to point sizes etc. The FONT element may be phased out in
future revisions to HTML.

size
     This sets the font size for the contents of the font element. You can
     set size to an integer ranging from 1 to 7 for an absolute font size,
     or specify a relative font size with a signed integer value, e.g.
     size="+1" or size="-2". This is mapped to an absolute font size by
     adding the current base font size as set by the BASEFONT element (see
     below).
color
     Used to set the color to stroke the text. Colors are given as RGB in
     hexadecimal notation or as one of 16 widely understood color names
     defined as per the BGCOLOR attribute on the BODY element.

Some user agents also support a FACE attribute which accepts a comma
separated list of font names in order of preference. This is used to search
for an installed font with the corresponding name. FACE is not part of HTML
3.2.

The following shows the effects of setting font to absolute sizes:

size=1 size=2 size=3 size=4 size=5 size=6 size=7

The following shows the effect of relative font sizes using a base font size
of 3:

size=-4 size=-3 size=-2 size=-1 size=+1 size=+2 size=+3 size=+4

The same thing with a base font size of 6:

size=-4 size=-3 size=-2 size=-1 size=+1 size=+2 size=+3 size=+4

BASEFONT

<!ELEMENT BASEFONT - O EMPTY    -- base font size (1 to 7) -->
<!ATTLIST BASEFONT
    size    CDATA   #IMPLIED    -- e.g. size=4, defaults to 3 --
    >

Used to set the base font size. BASEFONT is an empty element so the end tag
is forbidden. The SIZE attribute is an integer value ranging from 1 to 7.
The base font size applies to the normal and preformatted text but not to
headings, except where these are modified using the FONT element with a
relative font size.

BR

Used to force a line break. This is an empty element so the end tag is
forbidden. The CLEAR attribute can be used to move down past floating images
on either margin. <BR CLEAR=LEFT> moves down past floating images on the
left margin, <BR CLEAR=RIGHT> does the same for floating images on the right
margin, while <BR CLEAR=ALL> does the same for such images on both left and
right margins.

MAP

The MAP element provides a mechanism for client-side image maps. These can
be placed in the same document or grouped in a separate document although
this isn't yet widely supported. The MAP element requires start and end
tags. It contains one or more AREA elements that specify hotzones on the
associated image and bind these hotzones to URLs.

<!ENTITY % SHAPE "(rect|circle|poly)">
<!ENTITY % COORDS "CDATA" -- comma separated list of numbers -->

<!ELEMENT MAP - - (AREA)+>
<!ATTLIST MAP
    name    CDATA   #REQUIRED
    >

<!ELEMENT AREA - O EMPTY>
<!ATTLIST AREA
    shape   %SHAPE  rect
    coords  %COORDS #IMPLIED  -- defines coordinates for shape --
    href    %URL    #IMPLIED  -- this region acts as hypertext link --
    nohref (nohref) #IMPLIED  -- this region has no action --
    alt     CDATA   #REQUIRED -- needed for non-graphical user agents --
    >

Here is a simple example for a graphical navigational toolbar:

<img src="navbar.gif" border=0 usemap="#map1">

<map name="map1">
 <area href=guide.html alt="Access Guide" shape=rect coords="0,0,118,28">
 <area href=search.html alt="Search" shape=rect coords="184,0,276,28">
 <area href=shortcut.html alt="Go" shape=rect coords="118,0,184,28">
 <area href=top10.html alt="Top Ten" shape=rect coords="276,0,373,28">
</map>

The MAP element has one attribute NAME which is used to associate a name
with a map. This is then used by the USEMAP attribute on the IMG element to
reference the map via a URL fragment identifier. Note that the value of the
NAME attribute is case sensitive.

The AREA element is an empty element and so the end tag is forbidden. It
takes the following attributes: SHAPE, COORDS, HREF, NOHREF and ALT. The
SHAPE and COORDS attributes define a region on the image. If the SHAPE
attribute is omitted, SHAPE="RECT" is assumed.

     shape=rect coords="left-x, top-y, right-x, bottom-y"

     shape=circle coords="center-x, center-y, radius"

     shape=poly coords="x1,y1, x2,y2, x3,y3, ..."

Where x and y are measured in pixels from the left/top of the associated
image. If x and y values are given with a percent sign as a suffix, the
values should be interpreted as percentages of the image's width and height,
respectively. For example:

   SHAPE=RECT COORDS="0, 0, 50%, 100%"

The HREF attribute gives a URL for the target of the hypertext link. The
NOHREF attribute is used when you want to define a region that doesn't act
as a hotzone. This is useful when you want to cut a hole in an underlying
region acting as a hotzone.

If two or more regions overlap, the region defined first in the map
definition takes precedence over subsequent regions. This means that AREA
elements with NOHREF should generally be placed before ones with the HREF
attribute.

The ALT attribute is used to provide text labels which can be displayed in
the status line as the mouse or other pointing device is moved over
hotzones, or for constructing a textual menu for non-graphical user agents.
Authors are strongly recommended to provide meaningful ALT attributes to
support interoperability with speech-based or text-only user agents.
  ------------------------------------------------------------------------

Sample SGML Open Catalog for HTML 3.2

This can be used with an SGML parser like nsgmls to verify that files
conform to the HTML 3.2 DTD. It assumes that the DTD has been saved as the
file "HTML32.dtd" and that the Latin-1 entities are in the file
"ISOlat1.ent".

-- html32.soc: catalog for parsing HTML 3.2 documents --
SGMLDECL "HTML32.dcl"
PUBLIC "-//W3C//DTD HTML 3.2 Final//EN" HTML32.dtd
PUBLIC "-//W3C//DTD HTML 3.2 Draft//EN" HTML32.dtd
PUBLIC "-//W3C//DTD HTML 3.2//EN" HTML32.dtd
PUBLIC "ISO 8879-1986//ENTITIES Added Latin 1//EN//HTML" ISOlat1.ent

  ------------------------------------------------------------------------

SGML Declaration for HTML 3.2

This uses the 8 bit ISO Latin-1 character set. The size limits on properties
like literals and tag names have been considerably increased from their HTML
2.0 values, but it is recommended that user agents avoid imposing arbitrary
length limits.

<!SGML  "ISO 8879:1986"
   --
        SGML Declaration for HyperText Markup Language version 3.2

        With support for ISO Latin-1 and increased limits
        for tag and literal lengths etc.
   --

   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        200000
              GRPCAP          150000
              ENTCAP          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
              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 65536
               LITLEN   65536
               NAMELEN  65536
               PILEN    65536
               TAGLVL   100
               TAGLEN   65536
               GRPGTCNT 150
               GRPCNT   64

   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      NONE
>

  ------------------------------------------------------------------------

HTML 3.2 Document Type Definition

<!--
        W3C Document Type Definition for the HyperText Markup Language
        version 3.2 as ratified by a vote of W3C member companies.
        For more information on W3C look at  URL http://www.w3.org/

        Date: Tuesday January 14th 1997

        Author: Dave Raggett <dsr@w3.org>

        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).
        Widely deployed rendering attributes are included where they
        have been shown to be interoperable. SCRIPT and STYLE are
        included to smooth the introduction of client-side scripts
        and style sheets. Browsers must avoid showing the contents
        of these element Otherwise support for them is not required.
        ID, CLASS and STYLE attributes are not included in this version
        of HTML.
-->

<!ENTITY % HTML.Version
        "-//W3C//DTD HTML 3.2 Final//EN"

        -- Typical usage:

            <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
            <html>
            ...
            </html>
        --
        >

<!--================== Deprecated Features Switch =========================-->

<!ENTITY % HTML.Deprecated "INCLUDE">

<!--================== Imported Names =====================================-->

<!ENTITY % Content-Type "CDATA"
        -- meaning a MIME content type, as per RFC1521
        -->

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

<!ENTITY % URL "CDATA"
        -- The term URL means a CDATA attribute
           whose value is a Uniform Resource Locator,
           See RFC1808 (June 95) and RFC1738 (Dec 94).
        -->

<!-- Parameter Entities -->

<!ENTITY % head.misc "SCRIPT|STYLE|META|LINK" -- repeatable head elements -->

<!ENTITY % heading "H1|H2|H3|H4|H5|H6">

<!ENTITY % list "UL | OL |  DIR | MENU">

<![ %HTML.Deprecated [
    <!ENTITY % preformatted "PRE | XMP | LISTING">
]]>

<!ENTITY % preformatted "PRE">

<!--================ Character mnemonic entities ==========================-->

<!ENTITY % ISOlat1 PUBLIC
       "ISO 8879-1986//ENTITIES Added Latin 1//EN//HTML">
%ISOlat1;

<!--================ Entities for special symbols =========================-->
<!-- &trade and &cbsp are not widely deployed and so not included here -->

<!ENTITY amp    CDATA "&#38;"   -- ampersand          -->
<!ENTITY gt     CDATA "&#62;"   -- greater than       -->
<!ENTITY lt     CDATA "&#60;"   -- less than          -->

<!--=================== Text Markup =======================================-->

<!ENTITY % font "TT | I | B  | U | STRIKE | BIG | SMALL | SUB | SUP">

<!ENTITY % phrase "EM | STRONG | DFN | CODE | SAMP | KBD | VAR | CITE">

<!ENTITY % special "A | IMG | APPLET | FONT | BASEFONT | BR | SCRIPT | MAP">

<!ENTITY % form "INPUT | SELECT | TEXTAREA">

<!ENTITY % text "#PCDATA | %font | %phrase | %special | %form">

<!ELEMENT (%font|%phrase) - - (%text)*>

<!-- there are also 16 widely known color names although
  the resulting colors are implementation dependent:

   aqua, black, blue, fuchsia, gray, green, lime, maroon,
   navy, olive, purple, red, silver, teal, white, and yellow

 These colors were originally picked as being the standard
 16 colors supported with the Windows VGA palette.
 -->

<!ELEMENT FONT - - (%text)*     -- local change to font -->
<!ATTLIST FONT
    size    CDATA   #IMPLIED    -- [+]nn e.g. size="+1", size=4 --
    color   CDATA   #IMPLIED    -- #RRGGBB in hex, e.g. red: color="#FF0000" --
    >

<!ELEMENT BASEFONT - O EMPTY    -- base font size (1 to 7)-->
<!ATTLIST BASEFONT
    size    CDATA   #IMPLIED    -- e.g. size=3 --
    >

<!ELEMENT BR    - O EMPTY    -- forced line break -->
<!ATTLIST BR
        clear (left|all|right|none) none -- control of text flow --
        >

<!--================== HTML content models ================================-->
<!--
    HTML has three basic content models:

        %text       character level elements and text strings
        %flow       block-like elements e.g. paragraphs and lists
        %bodytext   as %flow plus headers H1-H6 and ADDRESS
-->

<!ENTITY % block
     "P | %list | %preformatted | DL | DIV | CENTER |
      BLOCKQUOTE | FORM | ISINDEX | HR | TABLE">

<!-- %flow is used for DD and LI -->

<!ENTITY % flow "(%text | %block)*">

<!--=================== Document Body =====================================-->

<!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 --
        >

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

<!ELEMENT ADDRESS - - %address.content>

<!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>

<!--================== The Anchor Element =================================-->

<!ELEMENT A - - (%text)* -(A)>
<!ATTLIST A
        name    CDATA   #IMPLIED    -- named link end --
        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 --
        >

<!--================== Client-side image maps ============================-->

<!-- These can be placed in the same document or grouped in a
     separate document although this isn't yet widely supported -->

<!ENTITY % SHAPE "(rect|circle|poly)">
<!ENTITY % COORDS "CDATA" -- comma separated list of numbers -->

<!ELEMENT MAP - - (AREA)*>
<!ATTLIST MAP
    name    CDATA   #IMPLIED
    >

<!ELEMENT AREA - O EMPTY>
<!ATTLIST AREA
    shape   %SHAPE  rect
    coords  %COORDS #IMPLIED  -- defines coordinates for shape --
    href    %URL    #IMPLIED  -- this region acts as hypertext link --
    nohref (nohref) #IMPLIED  -- this region has no action --
    alt     CDATA   #REQUIRED -- needed for non-graphical user agents --
    >

<!--================== The LINK Element ==================================-->

<!ENTITY % Types "CDATA"
        -- See Internet Draft: draft-ietf-html-relrev-00.txt
           LINK has been part of HTML since the early days
           although few browsers as yet take advantage of it.

           Relationship values can be used in principle:

                a) for document specific toolbars/menus when used
                   with the LINK element in the document head:
                b) to link to a separate style sheet
                c) to make a link to a script
                d) by stylesheets to control how collections of
                   html nodes are rendered into printed documents
                e) to make a link to a printable version of this document
                   e.g. a postscript or pdf version
-->

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

<!--=================== Images ============================================-->

<!ENTITY % Length "CDATA"   -- nn for pixels or nn% for percentage length -->
<!ENTITY % Pixels "NUMBER"  -- integer representing length in pixels -->

<!-- Suggested widths are used for negotiating image size
     with the module responsible for painting the image.
     align=left or right cause image to float to margin
     and for subsequent text to wrap around image -->

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

<!ELEMENT IMG    - O EMPTY --  Embedded image -->
<!ATTLIST IMG
        src     %URL     #REQUIRED  -- URL of image to embed --
        alt     CDATA    #IMPLIED   -- for display in place of image --
        align   %IAlign  #IMPLIED   -- vertical or horizontal alignment --
        height  %Pixels  #IMPLIED   -- suggested height in pixels --
        width   %Pixels  #IMPLIED   -- suggested width in pixels --
        border  %Pixels  #IMPLIED   -- suggested link border width --
        hspace  %Pixels  #IMPLIED   -- suggested horizontal gutter --
        vspace  %Pixels  #IMPLIED   -- suggested vertical gutter --
        usemap  %URL     #IMPLIED   -- use client-side image map --
        ismap   (ismap)  #IMPLIED   -- use server image map --
        >

<!-- USEMAP points to a MAP element which may be in this document
  or an external document, although the latter is not widely supported -->

<!--=================== Java APPLET tag ===================================-->
<!--
  This tag is supported by all Java enabled browsers. Applet resources
  (including their classes) are normally loaded relative to the document
  URL (or <BASE> element if it is defined). The CODEBASE attribute is used
  to change this default behavior. If the CODEBASE attribute is defined then
  it specifies a different location to find applet resources. The value
  can be an absolute URL or a relative URL. The absolute URL is used as is
  without modification and is not effected by the documents <BASE> element.
  When the codebase attribute is relative, then it is relative to the
  document URL (or <BASE> tag if defined).
-->
<!ELEMENT APPLET - - (PARAM | %text)*>
<!ATTLIST APPLET
        codebase %URL     #IMPLIED   -- code base --
        code     CDATA    #REQUIRED  -- class file --
        alt      CDATA    #IMPLIED   -- for display in place of applet --
        name     CDATA    #IMPLIED   -- applet name --
        width    %Pixels  #REQUIRED  -- suggested width in pixels --
        height   %Pixels  #REQUIRED  -- suggested height in pixels --
        align    %IAlign  #IMPLIED   -- vertical or horizontal alignment --
        hspace   %Pixels  #IMPLIED   -- suggested horizontal gutter --
        vspace   %Pixels  #IMPLIED   -- suggested vertical gutter --
        >

<!ELEMENT PARAM - O EMPTY>
<!ATTLIST PARAM
        name    NMTOKEN   #REQUIRED  -- The name of the parameter --
        value   CDATA     #IMPLIED   -- The value of the parameter --
        >

<!--
Here is an example:

    <applet codebase="applets/NervousText"
        code=NervousText.class
        width=300
        height=50>
    <param name=text value="Java is Cool!">
    <img src=sorry.gif alt="This looks better with Java support">
    </applet>
-->

<!--=================== Horizontal Rule ===================================-->

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

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

<!--=================== 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
        >

<!--=================== Preformatted Text =================================-->

<!-- excludes images and changes in font size -->

<!ENTITY % pre.exclusion "IMG|BIG|SMALL|SUB|SUP|FONT">

<!ELEMENT PRE - - (%text)* -(%pre.exclusion)>
<!ATTLIST PRE
        width NUMBER #implied -- is this widely supported? --
        >

<![ %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>

]]>

<!--=================== Block-like Quotes =================================-->

<!ELEMENT BLOCKQUOTE - - %body.content>

<!--=================== Lists =============================================-->

<!--
    HTML 3.2 allows you to control the sequence number for ordered lists.
    You can set the sequence number with the START and VALUE attributes.
    The TYPE attribute may be used to specify the rendering of ordered
    and unordered 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;>

<!-- Ordered lists OL, and unordered lists UL -->
<!ELEMENT (OL|UL) - -  (LI)+>

<!--
       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, ...

    The style is applied to the sequence number which by default
    is reset to 1 for the first list item in an ordered list.

    This can't be expressed directly in SGML due to case folding.
-->

<!ENTITY % OLStyle "CDATA" -- constrained to: [1|a|A|i|I] -->

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

<!-- bullet styles -->

<!ENTITY % ULStyle "disc|square|circle">

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

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

<!-- <DIR>              Directory list                  -->
<!-- <DIR COMPACT>      Compact list style              -->
<!-- <MENU>             Menu list                       -->
<!-- <MENU COMPACT>     Compact list style              -->

<!-- The type attribute can be used to change the bullet style
     in unordered lists and the numbering style in ordered lists -->

<!ENTITY % LIStyle "CDATA" -- constrained to: "(%ULStyle|%OLStyle)" -->

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

<!--================ Forms ===============================================-->

<!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"
        >

<!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 -- max chars allowed in text fields --
        src   %URL    #IMPLIED   -- for fields with background images --
        align %IAlign #IMPLIED   -- vertical or horizontal alignment --
        >

<!ELEMENT SELECT - - (OPTION+)>
<!ATTLIST SELECT
        name CDATA #REQUIRED
        size NUMBER #IMPLIED
        multiple (multiple) #IMPLIED
        >

<!ELEMENT OPTION - O (#PCDATA)*>
<!ATTLIST OPTION
        selected (selected) #IMPLIED
        value  CDATA  #IMPLIED -- defaults to element content --
        >

<!-- Multi-line text input field. -->

<!ELEMENT TEXTAREA - - (#PCDATA)*>
<!ATTLIST TEXTAREA
        name CDATA #REQUIRED
        rows NUMBER #REQUIRED
        cols NUMBER #REQUIRED
        >

<!--======================= Tables ========================================-->

<!-- Widely deployed subset of the full table standard, see RFC 1942
     e.g. at http://www.ics.uci.edu/pub/ietf/html/rfc1942.txt -->

<!-- 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 cell --
        %cell.valign;              -- vertical alignment in cell --
        width   %Pixels  #IMPLIED  -- suggested width for cell --
        height  %Pixels  #IMPLIED  -- suggested height for cell --
        >

<!--================ Document Head ========================================-->

<!-- %head.misc defined earlier on as "SCRIPT|STYLE|META|LINK" -->

<!ENTITY % head.content "TITLE & ISINDEX? & BASE?">

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

<!ELEMENT TITLE - -  (#PCDATA)* -(%head.misc)
          -- The TITLE element is not considered part of the flow of text.
             It should be displayed, for example as the page header or
             window title.
          -->

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

<!--
    The BASE element gives an absolute URL for dereferencing relative
    URLs, e.g.

         <BASE href="http://foo.com/index.html">
         ...
         <IMG SRC="images/bar.gif">

    The image is deferenced to

         http://foo.com/images/bar.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.
-->

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

<!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     --
        >

<!-- SCRIPT/STYLE are place holders for transition to next version of HTML -->

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

<!--================ Document Structure ===================================-->

<!ENTITY % version.attr "VERSION CDATA #FIXED '%HTML.Version;'">

<![ %HTML.Deprecated [
    <!ENTITY % html.content "HEAD, BODY, PLAINTEXT?">
]]>

<!ENTITY % html.content "HEAD, BODY">

<!ELEMENT HTML O O  (%html.content)>
<!ATTLIST HTML
        %version.attr;
        >

  ------------------------------------------------------------------------

Character Entities for ISO Latin-1

<!-- (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, provided this notice is included in all copies.
     This has been extended for use with HTML to cover the full
     set of codes in the range 160-255 decimal.
-->
<!-- Character entity set. Typical invocation:
     <!ENTITY % ISOlat1 PUBLIC
       "ISO 8879-1986//ENTITIES Added Latin 1//EN//HTML">
     %ISOlat1;
-->
    <!ENTITY nbsp   CDATA "&#160;" -- no-break space -->
    <!ENTITY iexcl  CDATA "&#161;" -- inverted exclamation mark -->
    <!ENTITY cent   CDATA "&#162;" -- cent sign -->
    <!ENTITY pound  CDATA "&#163;" -- pound sterling sign -->
    <!ENTITY curren CDATA "&#164;" -- general currency sign -->
    <!ENTITY yen    CDATA "&#165;" -- yen sign -->
    <!ENTITY brvbar CDATA "&#166;" -- broken (vertical) bar -->
    <!ENTITY sect   CDATA "&#167;" -- section sign -->
    <!ENTITY uml    CDATA "&#168;" -- umlaut (dieresis) -->
    <!ENTITY copy   CDATA "&#169;" -- copyright sign -->
    <!ENTITY ordf   CDATA "&#170;" -- ordinal indicator, feminine -->
    <!ENTITY laquo  CDATA "&#171;" -- angle quotation mark, left -->
    <!ENTITY not    CDATA "&#172;" -- not sign -->
    <!ENTITY shy    CDATA "&#173;" -- soft hyphen -->
    <!ENTITY reg    CDATA "&#174;" -- registered sign -->
    <!ENTITY macr   CDATA "&#175;" -- macron -->
    <!ENTITY deg    CDATA "&#176;" -- degree sign -->
    <!ENTITY plusmn CDATA "&#177;" -- plus-or-minus sign -->
    <!ENTITY sup2   CDATA "&#178;" -- superscript two -->
    <!ENTITY sup3   CDATA "&#179;" -- superscript three -->
    <!ENTITY acute  CDATA "&#180;" -- acute accent -->
    <!ENTITY micro  CDATA "&#181;" -- micro sign -->
    <!ENTITY para   CDATA "&#182;" -- pilcrow (paragraph sign) -->
    <!ENTITY middot CDATA "&#183;" -- middle dot -->
    <!ENTITY cedil  CDATA "&#184;" -- cedilla -->
    <!ENTITY sup1   CDATA "&#185;" -- superscript one -->
    <!ENTITY ordm   CDATA "&#186;" -- ordinal indicator, masculine -->
    <!ENTITY raquo  CDATA "&#187;" -- angle quotation mark, right -->
    <!ENTITY frac14 CDATA "&#188;" -- fraction one-quarter -->
    <!ENTITY frac12 CDATA "&#189;" -- fraction one-half -->
    <!ENTITY frac34 CDATA "&#190;" -- fraction three-quarters -->
    <!ENTITY iquest CDATA "&#191;" -- inverted question mark -->
    <!ENTITY Agrave CDATA "&#192;" -- capital A, grave accent -->
    <!ENTITY Aacute CDATA "&#193;" -- capital A, acute accent -->
    <!ENTITY Acirc  CDATA "&#194;" -- capital A, circumflex accent -->
    <!ENTITY Atilde CDATA "&#195;" -- capital A, tilde -->
    <!ENTITY Auml   CDATA "&#196;" -- capital A, dieresis or umlaut mark -->
    <!ENTITY Aring  CDATA "&#197;" -- capital A, ring -->
    <!ENTITY AElig  CDATA "&#198;" -- capital AE diphthong (ligature) -->
    <!ENTITY Ccedil CDATA "&#199;" -- capital C, cedilla -->
    <!ENTITY Egrave CDATA "&#200;" -- capital E, grave accent -->
    <!ENTITY Eacute CDATA "&#201;" -- capital E, acute accent -->
    <!ENTITY Ecirc  CDATA "&#202;" -- capital E, circumflex accent -->
    <!ENTITY Euml   CDATA "&#203;" -- capital E, dieresis or umlaut mark -->
    <!ENTITY Igrave CDATA "&#204;" -- capital I, grave accent -->
    <!ENTITY Iacute CDATA "&#205;" -- capital I, acute accent -->
    <!ENTITY Icirc  CDATA "&#206;" -- capital I, circumflex accent -->
    <!ENTITY Iuml   CDATA "&#207;" -- capital I, dieresis or umlaut mark -->
    <!ENTITY ETH    CDATA "&#208;" -- capital Eth, Icelandic -->
    <!ENTITY Ntilde CDATA "&#209;" -- capital N, tilde -->
    <!ENTITY Ograve CDATA "&#210;" -- capital O, grave accent -->
    <!ENTITY Oacute CDATA "&#211;" -- capital O, acute accent -->
    <!ENTITY Ocirc  CDATA "&#212;" -- capital O, circumflex accent -->
    <!ENTITY Otilde CDATA "&#213;" -- capital O, tilde -->
    <!ENTITY Ouml   CDATA "&#214;" -- capital O, dieresis or umlaut mark -->
    <!ENTITY times  CDATA "&#215;" -- multiply sign -->
    <!ENTITY Oslash CDATA "&#216;" -- capital O, slash -->
    <!ENTITY Ugrave CDATA "&#217;" -- capital U, grave accent -->
    <!ENTITY Uacute CDATA "&#218;" -- capital U, acute accent -->
    <!ENTITY Ucirc  CDATA "&#219;" -- capital U, circumflex accent -->
    <!ENTITY Uuml   CDATA "&#220;" -- capital U, dieresis or umlaut mark -->
    <!ENTITY Yacute CDATA "&#221;" -- capital Y, acute accent -->
    <!ENTITY THORN  CDATA "&#222;" -- capital THORN, Icelandic -->
    <!ENTITY szlig  CDATA "&#223;" -- small sharp s, German (sz ligature) -->
    <!ENTITY agrave CDATA "&#224;" -- small a, grave accent -->
    <!ENTITY aacute CDATA "&#225;" -- small a, acute accent -->
    <!ENTITY acirc  CDATA "&#226;" -- small a, circumflex accent -->
    <!ENTITY atilde CDATA "&#227;" -- small a, tilde -->
    <!ENTITY auml   CDATA "&#228;" -- small a, dieresis or umlaut mark -->
    <!ENTITY aring  CDATA "&#229;" -- small a, ring -->
    <!ENTITY aelig  CDATA "&#230;" -- small ae diphthong (ligature) -->
    <!ENTITY ccedil CDATA "&#231;" -- small c, cedilla -->
    <!ENTITY egrave CDATA "&#232;" -- small e, grave accent -->
    <!ENTITY eacute CDATA "&#233;" -- small e, acute accent -->
    <!ENTITY ecirc  CDATA "&#234;" -- small e, circumflex accent -->
    <!ENTITY euml   CDATA "&#235;" -- small e, dieresis or umlaut mark -->
    <!ENTITY igrave CDATA "&#236;" -- small i, grave accent -->
    <!ENTITY iacute CDATA "&#237;" -- small i, acute accent -->
    <!ENTITY icirc  CDATA "&#238;" -- small i, circumflex accent -->
    <!ENTITY iuml   CDATA "&#239;" -- small i, dieresis or umlaut mark -->
    <!ENTITY eth    CDATA "&#240;" -- small eth, Icelandic -->
    <!ENTITY ntilde CDATA "&#241;" -- small n, tilde -->
    <!ENTITY ograve CDATA "&#242;" -- small o, grave accent -->
    <!ENTITY oacute CDATA "&#243;" -- small o, acute accent -->
    <!ENTITY ocirc  CDATA "&#244;" -- small o, circumflex accent -->
    <!ENTITY otilde CDATA "&#245;" -- small o, tilde -->
    <!ENTITY ouml   CDATA "&#246;" -- small o, dieresis or umlaut mark -->
    <!ENTITY divide CDATA "&#247;" -- divide sign -->
    <!ENTITY oslash CDATA "&#248;" -- small o, slash -->
    <!ENTITY ugrave CDATA "&#249;" -- small u, grave accent -->
    <!ENTITY uacute CDATA "&#250;" -- small u, acute accent -->
    <!ENTITY ucirc  CDATA "&#251;" -- small u, circumflex accent -->
    <!ENTITY uuml   CDATA "&#252;" -- small u, dieresis or umlaut mark -->
    <!ENTITY yacute CDATA "&#253;" -- small y, acute accent -->
    <!ENTITY thorn  CDATA "&#254;" -- small thorn, Icelandic -->
    <!ENTITY yuml   CDATA "&#255;" -- small y, dieresis or umlaut mark -->

  ------------------------------------------------------------------------

Table of printable Latin-1 Character codes

[Image]
  ------------------------------------------------------------------------

Acknowledgements

The author would like to thank the members of the W3C HTML Editorial Review
Board, members of the W3C staff, and the many other people who have
contributed to this specification.
  ------------------------------------------------------------------------

Further Reading

The World Wide Web Consortium
     Further information on W3C activities and pointers to the status of
     work on HTML and HTTP etc. can be found at http://www.w3.org/. Further
     information on HTML in particular can be found at
     http://www.w3.org/pub/WWW/MarkUp/.
HTML 2.0 (RFC1866)
     By Tim Berners-Lee and Dan Connolly, November 1995. Defines the
     Hypertext Markup Language Specification Version 2.0. Available from
     ftp://ds.internic.net/rfc/rfc1866.txt.
Form-based File Upload in HTML (RFC1867)
     By E. Nebel and L. Masinter, November 1995. Describes extensions to
     HTML 2.0 (RFC1866) to support file upload from HTML forms. Available
     from ftp://ds.internic.net/rfc/rfc1867.txt.
HTML Tables (RFC1942)
     By Dave Raggett, May 1996. This defines the HTML table model. It is a
     superset of the table model defined by HTML 3.2. Available from
     ftp://ds.internic.net/rfc/rfc1942.txt, or as a W3C working draft at
     http://www.w3.org/pub/WWW/TR/WD-tables.
A Lexical Analyzer for HTML and Basic SGML
     By Dan Connolly, June 1996. Describes lexical considerations for
     parsing HTML documents. Available from
     http://www.w3.org/pub/WWW/TR/WD-html-lex
The Hypertext Transfer Protocol (HTTP)
     Further information of HTTP can be found at:
     http://www.w3.org/pub/WWW/Protocols.
A Standard Default Color Space for the Internet - sRGB
     By Michael Stokes, Mathew Anderson, Srinivasan Chandrasekar and Ricardo
     Motta, November 1996. Available from:
     http://www.w3.org/pub/WWW/Graphics/Color/sR