© Martin Bryan 1997 from SGML and HTML Explained published by Addison Wesley Longman
In this chapter the rules for creating SGML DTDs described in the preceding chapters are used to identify the significant features of the strict variant of Version 4.0 of the HTML DTD, as defined at the 7th November 1997. The way in which the elements defined in this DTD can be used to mark-up documents are covered in detail in the following chapters.
Note: To make it easier to explain the DTD I have reordered some of the sections, but only in situations where reordering does not affect interpretation of the DTD.
This chapter is split into the following sections, which reflects the sectioning applied in the HTML DTD:
A good indication of the quality of a DTD can often be found at the very start. If the DTD starts with a comprehensive record of its development history, in the form of an SGML comment declaration, you can be sure that the DTD has been developed as the result of extensive evaluation and testing. The experimental HTML 4.0 DTD is an example of a history statement for a DTD that is still undergoing review:
<!--
This is an EXPERIMENTAL version of the HTML 4.0 DTD which
excludes presentation attributes and elements that W3C expects
to phase out as support for style sheets matures. If you need
these features please use the transitional DTD. HTML 4.0
includes mechanisms for style sheets, scripting, embedding
objects, improved support for right to left and mixed direction
text, and enhancements to forms for improved accessibility for
people with disabilities.
Draft: $Date: 1997/11/07 15:32:37 $
Authors:
Dave Raggett <dsr@w3c.org>
Arnaud Le Hors <lehors@w3c.org>
This is work in progress, subject to change at any time.
It does not imply endorsement by, or the consensus of,
either W3C or members of the HTML working group. Further
information about HTML 4.0 is available at:
http://www.w3.org/TR/PR-html40
-->
Note particularly the dating of the draft, and a clear indication of how to contact its authors.
DTDs that are intended to be widely used should always be assigned a
formal public identifier (FPI). A good DTD will
contain a comment showing how the FPI can be used in a <!DOCTYPE
declaration to invoke the element set. In the case of the HTML DTD this comment
has been added to a parameter entity provided
to record the HTML version, which can be used to check the encoding of a
document as an attribute of the <HTML> element. The
parameter entity definition includes a comment
that shows the overall structure of an HTML document and identifies a set of
Uniform Resource Locators (URLs) from which the various
versions of the DTD, and the entity sets it references, can be obtained using
the Internet HyperText Transfer Protocol (HTTP).
<!ENTITY % HTML.Version "-//W3C//DTD HTML 4.0//EN"
-- Typical usage:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN"
"http://www.w3.org/TR/PR-html40/strict.dtd">
<html>
<head>
...
</head>
<body>
...
</body>
</html>
The URL used as a system identifier with the public identifier allows
the user agent to download the DTD and entity sets as needed.
The FPI for the transitional HTML 4.0 DTD is:
"-//W3C//DTD HTML 4.0 Transitional//EN
and its URL is:
http://www.w3.org/TR/PR-html40/loose.dtd
If you are writing a frameset document you should use the
following FPI:
"-//W3C//DTD HTML 4.0 Frameset//EN"
with the URL:
http://www.w3.org/TR/PR-html40/frameset.dtd
The following URLs are supported in relation to HTML 4.0
"http://www.w3.org/TR/PR-html40/strict.dtd" (Strict DTD)
"http://www.w3.org/TR/PR-html40/loose.dtd" (Loose DTD)
"http://www.w3.org/TR/PR-html40/frameset.dtd" (Frameset DTD)
"http://www.w3.org/TR/PR-html40/HTMLlat1.ent" (Latin-1 entities)
"http://www.w3.org/TR/PR-html40/HTMLsymbol.ent" (Symbol entities)
"http://www.w3.org/TR/PR-html40/HTMLspecial.ent" (Special entities)
These URLs point to the latest version of each file. To reference
this specific revision use the following URLs:
"http://www.w3.org/TR/PR-html40-971107/strict.dtd"
"http://www.w3.org/TR/PR-html40-971107/loose.dtd"
"http://www.w3.org/TR/PR-html40-971107/frameset.dtd"
"http://www.w3.org/TR/PR-html40-971107/HTMLlat1.ent"
"http://www.w3.org/TR/PR-html40-971107/HTMLsymbol.ent"
"http://www.w3.org/TR/PR-html40-971107/HTMLspecial.ent"
-->
Note: Only the elements and attributes covered in the strict version of the DTD are covered in this book.
While most DTDs use notation declarations to identify entities containing types of data other than SGML, the nature of the World Wide Web requires a different mechanism for handling references to externally stored data units. For HTML, external refererences are based on the concepts of Uniform Resource Locators (URLs), Multipurpose Internet Mail Extension (MIME) Internet media types, ISO standard dates/times, ISO and IETF language codes, scripts (such as JavaScript and VBScript) and various optional features, which have been formally defined in Request For Comment (RFC) documents issued by the Internet Engineering Task Force (IETF).
To make it clear where each of these specifications applies to the use of the DTD the following parameter entities have been declared.
<!--================== Imported Names ====================================-->
<!ENTITY % ContentType "CDATA"
-- media type, as per [RFC2045]
-->
<!ENTITY % ContentTypes "CDATA"
-- comma-separated list of media types, as per [RFC2045]
-->
<!ENTITY % Charset "CDATA"
-- a character encoding, as per [RFC2045]
-->
<!ENTITY % Charsets "CDATA"
-- a space separated list of character encodings, as per [RFC2045]
-->
<!ENTITY % LanguageCode "NAME"
-- a language code, as per [RFC1766]
-->
<!ENTITY % Character "CDATA"
-- a single character from [ISO10646]
-->
<!ENTITY % LinkTypes "CDATA"
-- space-separated list of link types
-->
<!ENTITY % MediaDesc "CDATA"
-- single or comma-separated list of media descriptors
-->
<!ENTITY % URL "CDATA"
-- a Uniform Resource Locator,
see [RFC1808] and [RFC1738]
-->
<!ENTITY % Datetime "CDATA" -- date and time information. ISO date format -->
<!ENTITY % Script "CDATA" -- script expression -->
<!ENTITY % FrameTarget "CDATA" -- render in this frame -->
<!ENTITY % Text "CDATA" -- render in this frame -->
The replacement text for each of these parameter entities is designed to be used as the declared value in an attribute declaration.
A number of SGML model groups are referenced at multiple points in the document. To ensure that these groups are declared before they are referenced they have been entered in a special part of the DTD, before any elements have been declared:
<!-- Parameter Entities --> <!ENTITY % head.misc "SCRIPT|STYLE|META|LINK" -- repeatable head elements --> <!ENTITY % heading "H1|H2|H3|H4|H5|H6"> <!ENTITY % list "UL | OL"> <!ENTITY % preformatted "PRE">
Note: Remember that parameter entities must always be declared before being referenced. For this reason it is good practice to keep such declarations in a separate section of the DTD, as has been done here.
The SGML declaration for Version 4.0 of HTML allows the multilingual ISO 10646 character set to be used as the content of HTML files.
In addition to a reference to the HTML-specific definition of a Latin 1 character set based on the ISO 8859-1 Latin 1 code set used to define the accented letters and symbols used by Western European languages, the new DTD provides entity sets definitions for a set of symbols of the type typically used in mathematical setting, and special typographic characters to allow users alternative ways of accessing these characters.
<!--================ Character mnemonic entities =========================--> <!ENTITY % HTMLlat1 PUBLIC "-//W3C//ENTITIES Latin1//EN//HTML" "http://www.w3.org/TR/PR-html40/HTMLlat1.ent"> %HTMLlat1; <!ENTITY % HTMLsymbol PUBLIC "-//W3C//ENTITIES Symbols//EN//HTML" "http://www.w3.org/TR/PR-html40/HTMLsymbol.ent"> %HTMLsymbol; <!ENTITY % HTMLspecial PUBLIC "-//W3C//ENTITIES Special//EN//HTML" "http://www.w3.org/TR/PR-html40/HTMLspecial.ent"> %HTMLspecial;
The HTML definition for the Latin 1 character set extends the ISO definitions by providing the characters list below. As with all definitions of HTML character entities the replacement text for each character is defined in terms of SGML numeric character references because such references will not be recognized by the parser as markup.
<!-- Portions (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.
-->
<!-- Character entity set. Typical invocation:
<!ENTITY % HTMLlat1 PUBLIC
"-//W3C//ENTITIES Full Latin 1//EN//HTML">
%HTMLlat1;
-->
<!ENTITY nbsp CDATA " " -- no-break space = non-breaking space,
U+00A0 ISOnum -->
<!ENTITY iexcl CDATA "¡" -- inverted exclamation mark, U+00A1 ISOnum -->
<!ENTITY cent CDATA "¢" -- cent sign, U+00A2 ISOnum -->
<!ENTITY pound CDATA "£" -- pound sign, U+00A3 ISOnum -->
<!ENTITY curren CDATA "¤" -- currency sign, U+00A4 ISOnum -->
<!ENTITY yen CDATA "¥" -- yen sign = yuan sign, U+00A5 ISOnum -->
<!ENTITY brvbar CDATA "¦" -- broken bar = broken vertical bar,
U+00A6 ISOnum -->
<!ENTITY sect CDATA "§" -- section sign, U+00A7 ISOnum -->
<!ENTITY uml CDATA "¨" -- diaeresis = spacing diaeresis,
U+00A8 ISOdia -->
<!ENTITY copy CDATA "©" -- copyright sign, U+00A9 ISOnum -->
<!ENTITY ordf CDATA "ª" -- feminine ordinal indicator, U+00AA ISOnum -->
<!ENTITY laquo CDATA "«" -- left-pointing double angle quotation mark
= left pointing guillemet, U+00AB ISOnum -->
<!ENTITY not CDATA "¬" -- not sign = discretionary hyphen,
U+00AC ISOnum -->
<!ENTITY shy CDATA "­" -- soft hyphen = discretionary hyphen,
U+00AD ISOnum -->
<!ENTITY reg CDATA "®" -- registered sign = registered trade mark sign,
U+00AE ISOnum -->
<!ENTITY macr CDATA "¯" -- macron = spacing macron = overline
= APL overbar, U+00AF ISOdia -->
<!ENTITY deg CDATA "°" -- degree sign, U+00B0 ISOnum -->
<!ENTITY plusmn CDATA "±" -- plus-minus sign = plus-or-minus sign,
U+00B1 ISOnum -->
<!ENTITY sup2 CDATA "²" -- superscript two = superscript digit two
= squared, U+00B2 ISOnum -->
<!ENTITY sup3 CDATA "³" -- superscript three = superscript digit three
= cubed, U+00B3 ISOnum -->
<!ENTITY acute CDATA "´" -- acute accent = spacing acute,
U+00B4 ISOdia -->
<!ENTITY micro CDATA "µ" -- micro sign, U+00B5 ISOnum -->
<!ENTITY para CDATA "¶" -- pilcrow sign = paragraph sign,
U+00B6 ISOnum -->
<!ENTITY middot CDATA "·" -- middle dot = Georgian comma
= Greek middle dot, U+00B7 ISOnum -->
<!ENTITY cedil CDATA "¸" -- cedilla = spacing cedilla, U+00B8 ISOdia -->
<!ENTITY sup1 CDATA "¹" -- superscript one = superscript digit one,
U+00B9 ISOnum -->
<!ENTITY ordm CDATA "º" -- masculine ordinal indicator,
U+00BA ISOnum -->
<!ENTITY raquo CDATA "»" -- right-pointing double angle quotation mark
= right pointing guillemet, U+00BB ISOnum -->
<!ENTITY frac14 CDATA "¼" -- vulgar fraction one quarter
= fraction one quarter, U+00BC ISOnum -->
<!ENTITY frac12 CDATA "½" -- vulgar fraction one half
= fraction one half, U+00BD ISOnum -->
<!ENTITY frac34 CDATA "¾" -- vulgar fraction three quarters
= fraction three quarters, U+00BE ISOnum -->
<!ENTITY iquest CDATA "¿" -- inverted question mark
= turned question mark, U+00BF ISOnum -->
<!ENTITY Agrave CDATA "À" -- latin capital letter A with grave
= latin capital letter A grave,
U+00C0 ISOlat1 -->
<!ENTITY Aacute CDATA "Á" -- latin capital letter A with acute,
U+00C1 ISOlat1 -->
<!ENTITY Acirc CDATA "Â" -- latin capital letter A with circumflex,
U+00C2 ISOlat1 -->
<!ENTITY Atilde CDATA "Ã" -- latin capital letter A with tilde,
U+00C3 ISOlat1 -->
<!ENTITY Auml CDATA "Ä" -- latin capital letter A with diaeresis,
U+00C4 ISOlat1 -->
<!ENTITY Aring CDATA "Å" -- latin capital letter A with ring above
= latin capital letter A ring,
U+00C5 ISOlat1 -->
<!ENTITY AElig CDATA "Æ" -- latin capital letter AE
= latin capital ligature AE,
U+00C6 ISOlat1 -->
<!ENTITY Ccedil CDATA "Ç" -- latin capital letter C with cedilla,
U+00C7 ISOlat1 -->
<!ENTITY Egrave CDATA "È" -- latin capital letter E with grave,
U+00C8 ISOlat1 -->
<!ENTITY Eacute CDATA "É" -- latin capital letter E with acute,
U+00C9 ISOlat1 -->
<!ENTITY Ecirc CDATA "Ê" -- latin capital letter E with circumflex,
U+00CA ISOlat1 -->
<!ENTITY Euml CDATA "Ë" -- latin capital letter E with diaeresis,
U+00CB ISOlat1 -->
<!ENTITY Igrave CDATA "Ì" -- latin capital letter I with grave,
U+00CC ISOlat1 -->
<!ENTITY Iacute CDATA "Í" -- latin capital letter I with acute,
U+00CD ISOlat1 -->
<!ENTITY Icirc CDATA "Î" -- latin capital letter I with circumflex,
U+00CE ISOlat1 -->
<!ENTITY Iuml CDATA "Ï" -- latin capital letter I with diaeresis,
U+00CF ISOlat1 -->
<!ENTITY ETH CDATA "Ð" -- latin capital letter ETH, U+00D0 ISOlat1 -->
<!ENTITY Ntilde CDATA "Ñ" -- latin capital letter N with tilde,
U+00D1 ISOlat1 -->
<!ENTITY Ograve CDATA "Ò" -- latin capital letter O with grave,
U+00D2 ISOlat1 -->
<!ENTITY Oacute CDATA "Ó" -- latin capital letter O with acute,
U+00D3 ISOlat1 -->
<!ENTITY Ocirc CDATA "Ô" -- latin capital letter O with circumflex,
U+00D4 ISOlat1 -->
<!ENTITY Otilde CDATA "Õ" -- latin capital letter O with tilde,
U+00D5 ISOlat1 -->
<!ENTITY Ouml CDATA "Ö" -- latin capital letter O with diaeresis,
U+00D6 ISOlat1 -->
<!ENTITY times CDATA "×" -- multiplication sign, U+00D7 ISOnum -->
<!ENTITY Oslash CDATA "Ø" -- latin capital letter O with stroke
= latin capital letter O slash,
U+00D8 ISOlat1 -->
<!ENTITY Ugrave CDATA "Ù" -- latin capital letter U with grave,
U+00D9 ISOlat1 -->
<!ENTITY Uacute CDATA "Ú" -- latin capital letter U with acute,
U+00DA ISOlat1 -->
<!ENTITY Ucirc CDATA "Û" -- latin capital letter U with circumflex,
U+00DB ISOlat1 -->
<!ENTITY Uuml CDATA "Ü" -- latin capital letter U with diaeresis,
U+00DC ISOlat1 -->
<!ENTITY Yacute CDATA "Ý" -- latin capital letter Y with acute,
U+00DD ISOlat1 -->
<!ENTITY THORN CDATA "Þ" -- latin capital letter THORN,
U+00DE ISOlat1 -->
<!ENTITY szlig CDATA "ß" -- latin small letter sharp s = ess-zed,
U+00DF ISOlat1 -->
<!ENTITY agrave CDATA "à" -- latin small letter a with grave
= latin small letter a grave,
U+00E0 ISOlat1 -->
<!ENTITY aacute CDATA "á" -- latin small letter a with acute,
U+00E1 ISOlat1 -->
<!ENTITY acirc CDATA "â" -- latin small letter a with circumflex,
U+00E2 ISOlat1 -->
<!ENTITY atilde CDATA "ã" -- latin small letter a with tilde,
U+00E3 ISOlat1 -->
<!ENTITY auml CDATA "ä" -- latin small letter a with diaeresis,
U+00E4 ISOlat1 -->
<!ENTITY aring CDATA "å" -- latin small letter a with ring above
= latin small letter a ring,
U+00E5 ISOlat1 -->
<!ENTITY aelig CDATA "æ" -- latin small letter ae
= latin small ligature ae, U+00E6 ISOlat1 -->
<!ENTITY ccedil CDATA "ç" -- latin small letter c with cedilla,
U+00E7 ISOlat1 -->
<!ENTITY egrave CDATA "è" -- latin small letter e with grave,
U+00E8 ISOlat1 -->
<!ENTITY eacute CDATA "é" -- latin small letter e with acute,
U+00E9 ISOlat1 -->
<!ENTITY ecirc CDATA "ê" -- latin small letter e with circumflex,
U+00EA ISOlat1 -->
<!ENTITY euml CDATA "ë" -- latin small letter e with diaeresis,
U+00EB ISOlat1 -->
<!ENTITY igrave CDATA "ì" -- latin small letter i with grave,
U+00EC ISOlat1 -->
<!ENTITY iacute CDATA "í" -- latin small letter i with acute,
U+00ED ISOlat1 -->
<!ENTITY icirc CDATA "î" -- latin small letter i with circumflex,
U+00EE ISOlat1 -->
<!ENTITY iuml CDATA "ï" -- latin small letter i with diaeresis,
U+00EF ISOlat1 -->
<!ENTITY eth CDATA "ð" -- latin small letter eth, U+00F0 ISOlat1 -->
<!ENTITY ntilde CDATA "ñ" -- latin small letter n with tilde,
U+00F1 ISOlat1 -->
<!ENTITY ograve CDATA "ò" -- latin small letter o with grave,
U+00F2 ISOlat1 -->
<!ENTITY oacute CDATA "ó" -- latin small letter o with acute,
U+00F3 ISOlat1 -->
<!ENTITY ocirc CDATA "ô" -- latin small letter o with circumflex,
U+00F4 ISOlat1 -->
<!ENTITY otilde CDATA "õ" -- latin small letter o with tilde,
U+00F5 ISOlat1 -->
<!ENTITY ouml CDATA "ö" -- latin small letter o with diaeresis,
U+00F6 ISOlat1 -->
<!ENTITY divide CDATA "÷" -- division sign, U+00F7 ISOnum -->
<!ENTITY oslash CDATA "ø" -- latin small letter o with stroke,
= latin small letter o slash,
U+00F8 ISOlat1 -->
<!ENTITY ugrave CDATA "ù" -- latin small letter u with grave,
U+00F9 ISOlat1 -->
<!ENTITY uacute CDATA "ú" -- latin small letter u with acute,
U+00FA ISOlat1 -->
<!ENTITY ucirc CDATA "û" -- latin small letter u with circumflex,
U+00FB ISOlat1 -->
<!ENTITY uuml CDATA "ü" -- latin small letter u with diaeresis,
U+00FC ISOlat1 -->
<!ENTITY yacute CDATA "ý" -- latin small letter y with acute,
U+00FD ISOlat1 -->
<!ENTITY thorn CDATA "þ" -- latin small letter thorn with,
U+00FE ISOlat1 -->
<!ENTITY yuml CDATA "ÿ" -- latin small letter y with diaeresis,
U+00FF ISOlat1 -->
Each definition ends with a comment that contains text describing the
relevant character, the Unicode hexidecimal representation of the characer code
point, beginning U+, and a note indicating which ISO character set
the character has been taken from.
In addition the following special symbols have been assigned names:
<!-- Special characters for HTML -->
<!-- Character entity set. Typical invocation:
<!ENTITY % HTMLspecial PUBLIC
"-//W3C//ENTITIES Special//EN//HTML">
%HTMLspecial; -->
<!-- Portions (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.
-->
<!-- Relevant ISO entity set is given unless names are newly introduced.
New names (i.e., not in ISO 8879 list) do not clash with any
existing ISO 8879 entity names. ISO 10646 character numbers
are given for each character, in hex. CDATA values are decimal
conversions of the ISO 10646 values and refer to the document
character set. Names are Unicode 2.0 names.
-->
<!-- C0 Controls and Basic Latin -->
<!ENTITY quot CDATA """ -- quotation mark = APL quote,
U+0022 ISOnum -->
<!ENTITY amp CDATA "&" -- ampersand, U+0026 ISOnum -->
<!ENTITY lt CDATA "<" -- less-than sign, U+003C ISOnum -->
<!ENTITY gt CDATA ">" -- greater-than sign, U+003E ISOnum -->
<!-- Latin Extended-A -->
<!ENTITY OElig CDATA "Œ" -- latin capital ligature OE,
U+0152 ISOlat2 -->
<!ENTITY oelig CDATA "œ" -- latin small ligature oe, U+0153 ISOlat2 -->
<!-- ligature is a misnomer, this is a separate character in some languages -->
<!ENTITY Scaron CDATA "Š" -- latin capital letter S with caron,
U+0160 ISOlat2 -->
<!ENTITY scaron CDATA "š" -- latin small letter s with caron,
U+0161 ISOlat2 -->
<!ENTITY Yuml CDATA "Ÿ" -- latin capital letter Y with diaeresis,
U+0178 ISOlat2 -->
<!-- Spacing Modifier Letters -->
<!ENTITY circ CDATA "ˆ" -- modifier letter circumflex accent,
U+02C6 ISOpub -->
<!ENTITY tilde CDATA "˜" -- small tilde, U+02DC ISOdia -->
<!-- General Punctuation -->
<!ENTITY ensp CDATA " " -- en space, U+2002 ISOpub -->
<!ENTITY emsp CDATA " " -- em space, U+2003 ISOpub -->
<!ENTITY thinsp CDATA " " -- thin space, U+2009 ISOpub -->
<!ENTITY zwnj CDATA "‌" -- zero width non-joiner,
U+200C NEW RFC 2070 -->
<!ENTITY zwj CDATA "‍" -- zero width joiner, U+200D NEW RFC 2070 -->
<!ENTITY lrm CDATA "‎" -- left-to-right mark, U+200E NEW RFC 2070 -->
<!ENTITY rlm CDATA "‏" -- right-to-left mark, U+200F NEW RFC 2070 -->
<!ENTITY ndash CDATA "–" -- en dash, U+2013 ISOpub -->
<!ENTITY mdash CDATA "—" -- em dash, U+2014 ISOpub -->
<!ENTITY lsquo CDATA "‘" -- left single quotation mark,
U+2018 ISOnum -->
<!ENTITY rsquo CDATA "’" -- right single quotation mark,
U+2019 ISOnum -->
<!ENTITY sbquo CDATA "‚" -- single low-9 quotation mark, U+201A NEW -->
<!ENTITY ldquo CDATA "“" -- left double quotation mark,
U+201C ISOnum -->
<!ENTITY rdquo CDATA "”" -- right double quotation mark,
U+201D ISOnum -->
<!ENTITY bdquo CDATA "„" -- double low-9 quotation mark, U+201E NEW -->
<!ENTITY dagger CDATA "†" -- dagger, U+2020 ISOpub -->
<!ENTITY Dagger CDATA "‡" -- double dagger, U+2021 ISOpub -->
<!ENTITY permil CDATA "‰" -- per mille sign, U+2030 ISOtech -->
<!ENTITY lsaquo CDATA "‹" -- single left-pointing angle quotation mark,
U+2039 ISO proposed -->
<!-- lsaquo is proposed but not yet ISO standardised -->
<!ENTITY rsaquo CDATA "›" -- single right-pointing angle quotation mark,
U+203A ISO proposed -->
<!-- rsaquo is proposed but not yet ISO standardised -->
<!ENTITY euro CDATA "€" -- euro sign, U+20AC NEW -->
Note particularly the entries whose comments end NEW RFC 2070.
These characters are required to support the new generation of bidirectional
document browsers, which can handle Hebrew, Arabic and Indic scripts. There are
also a number of characters that do not yet form part of the ISO character sets,
such as the Euro sign, which are simply flagged as being NEW
characters.
The named characters that can be used for mathematical setting are:
<!-- Mathematical, Greek and Symbolic characters for HTML -->
<!-- Character entity set. Typical invocation:
<!ENTITY % HTMLsymbol PUBLIC
"-//W3C//ENTITIES Symbolic//EN//HTML">
%HTMLsymbol; -->
<!-- Portions (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.
-->
<!-- Relevant ISO entity set is given unless names are newly introduced.
New names (i.e., not in ISO 8879 list) do not clash with any
existing ISO 8879 entity names. ISO 10646 character numbers
are given for each character, in hex. CDATA values are decimal
conversions of the ISO 10646 values and refer to the document
character set. Names are Unicode 2.0 names.
-->
<!-- Latin Extended-B -->
<!ENTITY fnof CDATA "ƒ" -- latin small f with hook = function
= florin, U+0192 ISOtech -->
<!-- Greek -->
<!ENTITY Alpha CDATA "Α" -- greek capital letter alpha, U+0391 -->
<!ENTITY Beta CDATA "Β" -- greek capital letter beta, U+0392 -->
<!ENTITY Gamma CDATA "Γ" -- greek capital letter gamma,
U+0393 ISOgrk3 -->
<!ENTITY Delta CDATA "Δ" -- greek capital letter delta,
U+0394 ISOgrk3 -->
<!ENTITY Epsilon CDATA "Ε" -- greek capital letter epsilon, U+0395 -->
<!ENTITY Zeta CDATA "Ζ" -- greek capital letter zeta, U+0396 -->
<!ENTITY Eta CDATA "Η" -- greek capital letter eta, U+0397 -->
<!ENTITY Theta CDATA "Θ" -- greek capital letter theta,
U+0398 ISOgrk3 -->
<!ENTITY Iota CDATA "Ι" -- greek capital letter iota, U+0399 -->
<!ENTITY Kappa CDATA "Κ" -- greek capital letter kappa, U+039A -->
<!ENTITY Lambda CDATA "Λ" -- greek capital letter lambda,
U+039B ISOgrk3 -->
<!ENTITY Mu CDATA "Μ" -- greek capital letter mu, U+039C -->
<!ENTITY Nu CDATA "Ν" -- greek capital letter nu, U+039D -->
<!ENTITY Xi CDATA "Ξ" -- greek capital letter xi, U+039E ISOgrk3 -->
<!ENTITY Omicron CDATA "Ο" -- greek capital letter omicron, U+039F -->
<!ENTITY Pi CDATA "Π" -- greek capital letter pi, U+03A0 ISOgrk3 -->
<!ENTITY Rho CDATA "Ρ" -- greek capital letter rho, U+03A1 -->
<!-- there is no Sigmaf, and no U+03A2 character either -->
<!ENTITY Sigma CDATA "Σ" -- greek capital letter sigma,
U+03A3 ISOgrk3 -->
<!ENTITY Tau CDATA "Τ" -- greek capital letter tau, U+03A4 -->
<!ENTITY Upsilon CDATA "Υ" -- greek capital letter upsilon,
U+03A5 ISOgrk3 -->
<!ENTITY Phi CDATA "Φ" -- greek capital letter phi,
U+03A6 ISOgrk3 -->
<!ENTITY Chi CDATA "Χ" -- greek capital letter chi, U+03A7 -->
<!ENTITY Psi CDATA "Ψ" -- greek capital letter psi,
U+03A8 ISOgrk3 -->
<!ENTITY Omega CDATA "Ω" -- greek capital letter omega,
U+03A9 ISOgrk3 -->
<!ENTITY alpha CDATA "α" -- greek small letter alpha,
U+03B1 ISOgrk3 -->
<!ENTITY beta CDATA "β" -- greek small letter beta, U+03B2 ISOgrk3 -->
<!ENTITY gamma CDATA "γ" -- greek small letter gamma,
U+03B3 ISOgrk3 -->
<!ENTITY delta CDATA "δ" -- greek small letter delta,
U+03B4 ISOgrk3 -->
<!ENTITY epsilon CDATA "ε" -- greek small letter epsilon,
U+03B5 ISOgrk3 -->
<!ENTITY zeta CDATA "ζ" -- greek small letter zeta, U+03B6 ISOgrk3 -->
<!ENTITY eta CDATA "η" -- greek small letter eta, U+03B7 ISOgrk3 -->
<!ENTITY theta CDATA "θ" -- greek small letter theta,
U+03B8 ISOgrk3 -->
<!ENTITY iota CDATA "ι" -- greek small letter iota, U+03B9 ISOgrk3 -->
<!ENTITY kappa CDATA "κ" -- greek small letter kappa,
U+03BA ISOgrk3 -->
<!ENTITY lambda CDATA "λ" -- greek small letter lambda,
U+03BB ISOgrk3 -->
<!ENTITY mu CDATA "μ" -- greek small letter mu, U+03BC ISOgrk3 -->
<!ENTITY nu CDATA "ν" -- greek small letter nu, U+03BD ISOgrk3 -->
<!ENTITY xi CDATA "ξ" -- greek small letter xi, U+03BE ISOgrk3 -->
<!ENTITY omicron CDATA "ο" -- greek small letter omicron, U+03BF NEW -->
<!ENTITY pi CDATA "π" -- greek small letter pi, U+03C0 ISOgrk3 -->
<!ENTITY rho CDATA "ρ" -- greek small letter rho, U+03C1 ISOgrk3 -->
<!ENTITY sigmaf CDATA "ς" -- greek small letter final sigma,
U+03C2 ISOgrk3 -->
<!ENTITY sigma CDATA "σ" -- greek small letter sigma,
U+03C3 ISOgrk3 -->
<!ENTITY tau CDATA "τ" -- greek small letter tau, U+03C4 ISOgrk3 -->
<!ENTITY upsilon CDATA "υ" -- greek small letter upsilon,
U+03C5 ISOgrk3 -->
<!ENTITY phi CDATA "φ" -- greek small letter phi, U+03C6 ISOgrk3 -->
<!ENTITY chi CDATA "χ" -- greek small letter chi, U+03C7 ISOgrk3 -->
<!ENTITY psi CDATA "ψ" -- greek small letter psi, U+03C8 ISOgrk3 -->
<!ENTITY omega CDATA "ω" -- greek small letter omega,
U+03C9 ISOgrk3 -->
<!ENTITY thetasym CDATA "ϑ" -- greek small letter theta symbol,
U+03D1 NEW -->
<!ENTITY upsih CDATA "ϒ" -- greek upsilon with hook symbol,
U+03D2 NEW -->
<!ENTITY piv CDATA "ϖ" -- greek pi symbol, U+03D6 ISOgrk3 -->
<!-- General Punctuation -->
<!ENTITY bull CDATA "•" -- bullet = black small circle,
U+2022 ISOpub -->
<!-- bullet is NOT the same as bullet operator, U+2219 -->
<!ENTITY hellip CDATA "…" -- horizontal ellipsis = three dot leader,
U+2026 ISOpub -->
<!ENTITY prime CDATA "′" -- prime = minutes = feet, U+2032 ISOtech -->
<!ENTITY Prime CDATA "″" -- double prime = seconds = inches,
U+2033 ISOtech -->
<!ENTITY oline CDATA "‾" -- overline = spacing overscore,
U+203E NEW -->
<!ENTITY frasl CDATA "⁄" -- fraction slash, U+2044 NEW -->
<!-- Letterlike Symbols -->
<!ENTITY weierp CDATA "℘" -- script capital P = power set
= Weierstrass p, U+2118 ISOamso -->
<!ENTITY image CDATA "ℑ" -- blackletter capital I = imaginary part,
U+2111 ISOamso -->
<!ENTITY real CDATA "ℜ" -- blackletter capital R = real part symbol,
U+211C ISOamso -->
<!ENTITY trade CDATA "™" -- trade mark sign, U+2122 ISOnum -->
<!ENTITY alefsym CDATA "ℵ" -- alef symbol = first transfinite cardinal,
U+2135 NEW -->
<!-- alef symbol is NOT the same as hebrew letter alef,
U+05D0 although the same glyph could be used to depict both characters -->
<!-- Arrows -->
<!ENTITY larr CDATA "←" -- leftwards arrow, U+2190 ISOnum -->
<!ENTITY uarr CDATA "↑" -- upwards arrow, U+2191 ISOnum-->
<!ENTITY rarr CDATA "→" -- rightwards arrow, U+2192 ISOnum -->
<!ENTITY darr CDATA "↓" -- downwards arrow, U+2193 ISOnum -->
<!ENTITY harr CDATA "↔" -- left right arrow, U+2194 ISOamsa -->
<!ENTITY crarr CDATA "↵" -- downwards arrow with corner leftwards
= carriage return, U+21B5 NEW -->
<!ENTITY lArr CDATA "⇐" -- leftwards double arrow, U+21D0 ISOtech -->
<!-- Unicode does not say that lArr is the same as the 'is implied by' arrow
but also does not have any other character for that function. So ? lArr can
be used for 'is implied by' as ISOtech suggests -->
<!ENTITY uArr CDATA "⇑" -- upwards double arrow, U+21D1 ISOamsa -->
<!ENTITY rArr CDATA "⇒" -- rightwards double arrow,
U+21D2 ISOtech -->
<!-- Unicode does not say this is the 'implies' character but does not have
another character with this function so ?
rArr can be used for 'implies' as ISOtech suggests -->
<!ENTITY dArr CDATA "⇓" -- downwards double arrow, U+21D3 ISOamsa -->
<!ENTITY hArr CDATA "⇔" -- left right double arrow,
U+21D4 ISOamsa -->
<!-- Mathematical Operators -->
<!ENTITY forall CDATA "∀" -- for all, U+2200 ISOtech -->
<!ENTITY part CDATA "∂" -- partial differential, U+2202 ISOtech -->
<!ENTITY exist CDATA "∃" -- there exists, U+2203 ISOtech -->
<!ENTITY empty CDATA "∅" -- empty set = null set = diameter,
U+2205 ISOamso -->
<!ENTITY nabla CDATA "∇" -- nabla = backward difference,
U+2207 ISOtech -->
<!ENTITY isin CDATA "∈" -- element of, U+2208 ISOtech -->
<!ENTITY notin CDATA "∉" -- not an element of, U+2209 ISOtech -->
<!ENTITY ni CDATA "∋" -- contains as member, U+220B ISOtech -->
<!-- should there be a more memorable name than 'ni'? -->
<!ENTITY prod CDATA "∏" -- n-ary product = product sign,
U+220F ISOamsb -->
<!-- prod is NOT the same character as U+03A0 'greek capital letter pi' though
the same glyph might be used for both -->
<!ENTITY sum CDATA "∑" -- n-ary sumation, U+2211 ISOamsb -->
<!-- sum is NOT the same character as U+03A3 'greek capital letter sigma'
though the same glyph might be used for both -->
<!ENTITY minus CDATA "−" -- minus sign, U+2212 ISOtech -->
<!ENTITY lowast CDATA "∗" -- asterisk operator, U+2217 ISOtech -->
<!ENTITY radic CDATA "√" -- square root = radical sign,
U+221A ISOtech -->
<!ENTITY prop CDATA "∝" -- proportional to, U+221D ISOtech -->
<!ENTITY infin CDATA "∞" -- infinity, U+221E ISOtech -->
<!ENTITY ang CDATA "∠" -- angle, U+2220 ISOamso -->
<!ENTITY and CDATA "∧" -- logical and = wedge, U+2227 ISOtech -->
<!ENTITY or CDATA "∨" -- logical or = vee, U+2228 ISOtech -->
<!ENTITY cap CDATA "∩" -- intersection = cap, U+2229 ISOtech -->
<!ENTITY cup CDATA "∪" -- union = cup, U+222A ISOtech -->
<!ENTITY int CDATA "∫" -- integral, U+222B ISOtech -->
<!ENTITY there4 CDATA "∴" -- therefore, U+2234 ISOtech -->
<!ENTITY sim CDATA "∼" -- tilde operator = varies with = similar to,
U+223C ISOtech -->
<!-- tilde operator is NOT the same character as the tilde, U+007E,
although the same glyph might be used to represent both -->
<!ENTITY cong CDATA "≅" -- approximately equal to, U+2245 ISOtech -->
<!ENTITY asymp CDATA "≈" -- almost equal to = asymptotic to,
U+2248 ISOamsr -->
<!ENTITY ne CDATA "≠" -- not equal to, U+2260 ISOtech -->
<!ENTITY equiv CDATA "≡" -- identical to, U+2261 ISOtech -->
<!ENTITY le CDATA "≤" -- less-than or equal to, U+2264 ISOtech -->
<!ENTITY ge CDATA "≥" -- greater-than or equal to,
U+2265 ISOtech -->
<!ENTITY sub CDATA "⊂" -- subset of, U+2282 ISOtech -->
<!ENTITY sup CDATA "⊃" -- superset of, U+2283 ISOtech -->
<!-- note that nsup, 'not a superset of, U+2283' is not covered by the Symbol
font encoding and is not included. Should it be, for symmetry?
It is in ISOamsn -->
<!ENTITY nsub CDATA "⊄" -- not a subset of, U+2284 ISOamsn -->
<!ENTITY sube CDATA "⊆" -- subset of or equal to, U+2286 ISOtech -->
<!ENTITY supe CDATA "⊇" -- superset of or equal to,
U+2287 ISOtech -->
<!ENTITY oplus CDATA "⊕" -- circled plus = direct sum,
U+2295 ISOamsb -->
<!ENTITY otimes CDATA "⊗" -- circled times = vector product,
U+2297 ISOamsb -->
<!ENTITY perp CDATA "⊥" -- up tack = orthogonal to = perpendicular,
U+22A5 ISOtech -->
<!ENTITY sdot CDATA "⋅" -- dot operator, U+22C5 ISOamsb -->
<!-- dot operator is NOT the same character as U+00B7 middle dot -->
<!-- Miscellaneous Technical -->
<!ENTITY lceil CDATA "⌈" -- left ceiling = apl upstile,
U+2308 ISOamsc -->
<!ENTITY rceil CDATA "⌉" -- right ceiling, U+2309 ISOamsc -->
<!ENTITY lfloor CDATA "⌊" -- left floor = apl downstile,
U+230A ISOamsc -->
<!ENTITY rfloor CDATA "⌋" -- right floor, U+230B ISOamsc -->
<!ENTITY lang CDATA "〈" -- left-pointing angle bracket = bra,
U+2329 ISOtech -->
<!-- lang is NOT the same character as U+003C 'less than'
or U+2039 'single left-pointing angle quotation mark' -->
<!ENTITY rang CDATA "〉" -- right-pointing angle bracket = ket,
U+232A ISOtech -->
<!-- rang is NOT the same character as U+003E 'greater than'
or U+203A 'single right-pointing angle quotation mark' -->
<!-- Geometric Shapes -->
<!ENTITY loz CDATA "◊" -- lozenge, U+25CA ISOpub -->
<!-- Miscellaneous Symbols -->
<!ENTITY spades CDATA "♠" -- black spade suit, U+2660 ISOpub -->
<!-- black here seems to mean filled as opposed to hollow -->
<!ENTITY clubs CDATA "♣" -- black club suit = shamrock,
U+2663 ISOpub -->
<!ENTITY hearts CDATA "♥" -- black heart suit = valentine,
U+2665 ISOpub -->
<!ENTITY diams CDATA "♦" -- black diamond suit, U+2666 ISOpub -->
Version 4.0 of the HTML DTD includes a number of attributes whose use is shared by different sets of elements. These have been split into three main groups, covering:
i18n within W3C because 18 is the number of characters skipped by
in the word internationalization);<!--=================== Generic Attributes ===============================--> <!ENTITY % coreattrs "id ID #IMPLIED -- document-wide unique id -- class CDATA #IMPLIED -- space separated list of classes -- style CDATA #IMPLIED -- associated style info -- title %Text; #IMPLIED -- advisory title/amplification --" > <!ENTITY % i18n "lang %LanguageCode; #IMPLIED -- language code -- dir (ltr|rtl) #IMPLIED -- direction for weak/neutral text --" > <!ENTITY % events "onclick %Script; #IMPLIED -- a pointer button was clicked -- ondblclick %Script; #IMPLIED -- a pointer button was double clicked -- onmousedown %Script; #IMPLIED -- a pointer button was pressed down -- onmouseup %Script; #IMPLIED -- a pointer button was released -- onmouseover %Script; #IMPLIED -- a pointer was moved onto -- onmousemove %Script; #IMPLIED -- a pointer was moved within -- onmouseout %Script; #IMPLIED -- a pointer was moved away -- onkeypress %Script; #IMPLIED -- a key was pressed and released -- onkeydown %Script; #IMPLIED -- a key was pressed down -- onkeyup %Script; #IMPLIED -- a key was released --" > <!ENTITY % attrs "%coreattrs; %i18n; %events;">
The %attrs parameter entity allows these sets to be defined
using a single parameter entity reference.
There are also a set of attributes, which by default are treated as part of an ignored marked section, that have been reserved for planned extensions to the DTD:
<!-- Reserved Feature Switch --> <!ENTITY % HTML.Reserved "IGNORE"> <!-- The following attributes are reserved for possible future use --> <![ %HTML.Reserved; [ <!ENTITY % reserved "datasrc %URL; #IMPLIED -- a single or tabular Data Source -- datafld CDATA #IMPLIED -- the property or column name -- dataformatas (plaintext|html) plaintext -- text or html --" > ]]> <!ENTITY % reserved "">
Note particularly that an empty replacement string has been defined for the
parameter entity in a declaration immediately following the ignored marked
section. If the HTML.Reserved parameter entity is changed to
INCLUDE the definition within the marked section will be read
before the one that follows it, and so will take precedence.
The next set of parameter entity declarations is used to simplify subsequent element declarations by providing an easy-to-understand name for groups of elements that share common characteristics:
<!--=================== Text Markup ======================================-->
<!ENTITY % fontstyle
"TT | I | B | BIG | SMALL">
<!ENTITY % phrase "EM | STRONG | DFN | CODE |
SAMP | KBD | VAR | CITE | ABBR">
<!ENTITY % special
"A | IMG | OBJECT | BR | SCRIPT | MAP | Q | SUB | SUP | SPAN | BDO">
<!ENTITY % formctrl "INPUT | SELECT | TEXTAREA | LABEL | BUTTON">
<!-- %inline; covers inline or "text-level" elements -->
<!ENTITY % inline "#PCDATA | %fontstyle; | %phrase; | %special; | %formctrl;">
The HTML DTD is particularly good in that it defines the most commonly used elements first, with the least commonly used elements afterwards. This technique can reduce the average amount of time spent searching for a definition considerably. The most used elements of the HTML DTD are those that can occur within paragraphs and other blocks of text. These elements identify phrases or text set in specific fonts. They share an infinitely recursive model:
<!ELEMENT (%fontstyle;|%phrase;) - - (%inline;)*> <!ATTLIST (%fontstyle;|%phrase;) %attrs; -- %coreattrs, %i18n, %events -- >
Note that, with this version of the HTML DTD, each embedded text element can
optionally have associated with it the default set of attributes that allow
users to add an SGML unique identifer, id,
a class specification, class, a style specification, style,
an RFC 1766 language identifier, lang, and a writing direction
indicator, dir, to the markup tag. In addition these elements can
also be assigned event-based attributes, though it is unclear what effect key
based actions will have on elements other than those used for forms (i.e. input
and text area fields.)
Note: As with all new HTML attributes, it will be some time before
browsers support their use. The HTML specification includes rules that ensure
that attributes that are not known to a particular browser will simply be
ignored. However, this can mean that the expected effect is not produced. This
is likely to be particularly true of the id attribute, which
should be referenceable through URLs in a similar fashion to the name
attribute of HTML anchors. It may be some time into 1998 before most browsers
can access links specified via SGML unique identifiers.
The following elements, which are new to this version of the DTD, allow
style, i18n and (somwhat surprisingly) event
generic attributes to be associated with:
<!ELEMENT (SUB|SUP) - - (%inline;)* -- subscript, superscript --> <!ATTLIST (SUB|SUP) %attrs; -- %coreattrs, %i18n, %events -- > <!ELEMENT SPAN - - (%inline;)* -- generic language/style container --> <!ATTLIST SPAN %attrs; -- %coreattrs, %i18n, %events -- charset %Charset; #IMPLIED -- char encoding of linked resource -- type %ContentType; #IMPLIED -- advisory content type -- href %URL; #IMPLIED -- URL for linked resource -- hreflang %LanguageCode; #IMPLIED -- language code -- target %FrameTarget; #IMPLIED -- render in this frame -- rel %LinkTypes; #IMPLIED -- forward link types -- rev %LinkTypes; #IMPLIED -- reverse link types -- media %MediaDesc; #IMPLIED -- for rendering on these media -- %reserved; -- reserved for possible future use -- >
Where a document contains multilingual text in which different languages
have different writing directions the biderectional over-ride (BDO)
element can be used to identify embedded text, such as numbers, for which an
alternative writing direction needs to be applied. In this case only the i18n
generic attributes apply.
<!ELEMENT BDO - - (%inline;)* -- I18N BiDi over-ride --> <!ATTLIST BDO %coreattrs; -- id, class, style, title -- lang %LanguageCode; #IMPLIED -- language code -- dir (ltr|rtl) #REQUIRED -- directionality -- >
The final element in the text markup group has been declared using SGML's
EMPTY keyword to indicate that
only a start-tag needs to be entered to mark the point at which action, in this
case a forced line break, is required:
<!ELEMENT BR - O EMPTY -- forced line break --> <!ATTLIST BR %coreattrs; -- id, class, style, title -- >
The following parameter entities are used to group together those elements which share common properties so that they can be sensibly referenced in the model for the main body of a document:
<!--================== HTML content models ===============================-->
<!--
HTML has two basic content models:
%inline; character level elements and text strings
%block; block-like elements e.g. paragraphs and lists
-->
<!ENTITY % block
"P | %heading; | %list; | %preformatted; | DL | DIV | NOSCRIPT |
BLOCKQUOTE | FORM | HR | TABLE | FIELDSET | ADDRESS">
<!ENTITY % flow "%block; | %inline;">
Note that the %flow; parameter entity combines the objects
defined as blocks with those defined earlier as forming the complete set of
in-line data elements.
The following elements are used to identify the main components of the body of the document. Their use is explained in detail in Chapter 13.
<!ELEMENT BODY O O (%block;|SCRIPT)+ +(INS|DEL) -- document body --> <!ATTLIST BODY %attrs; -- %coreattrs, %i18n, %events -- onload %Script; #IMPLIED -- the document has been loaded -- onunload %Script; #IMPLIED -- the document has been removed -- > <!ELEMENT ADDRESS - - (%inline;)* -- information on author --> <!ATTLIST ADDRESS %attrs; -- %coreattrs, %i18n, %events -- > <!ELEMENT DIV - - (%block;|SCRIPT)+ -- generic language/style container --> <!ATTLIST DIV %attrs; -- %coreattrs, %i18n, %events -- charset %Charset; #IMPLIED -- char encoding of linked resource -- type %ContentType; #IMPLIED -- advisory content type -- href %URL; #IMPLIED -- URL for linked resource -- hreflang %LanguageCode; #IMPLIED -- language code -- target %FrameTarget; #IMPLIED -- render in this frame -- rel %LinkTypes; #IMPLIED -- forward link types -- rev %LinkTypes; #IMPLIED -- reverse link types -- media %MediaDesc; #IMPLIED -- for rendering on these media -- %reserved; -- reserved for possible future use -- >
Note particularly the use of the use of %Script to indicate
that the CDATA content of the onload and
onunload attributes should be a reference to a function of the
type that can defined within a <SCRIPT> element. This shows
how an informal form of attribute typing can be defined in a DTD without having
to make use of
HyTime lexical type definitions. Other
examples of the same technique are used to type the various attributes of the
division (DIV) element, such as the %URL parameter
entity reference to indicate that the CDATA content of the href
attribute of a should be a valid URL.
Note also the use of an inclusion exception
to allow sections of inserted (INS) and deleted (DEL)
material to be identified anywhere in the body of the document. These elements
are defined, somewhat later in the DTD, as:
<!--=================== Inserted/Deleted Text ============================--> <!-- INS/DEL are handled by inclusion on BODY --> <!ELEMENT (INS|DEL) - - (%flow;)* -- inserted text, deleted text --> <!ATTLIST (INS|DEL) %attrs; -- %coreattrs, %i18n, %events -- cite %URL; #IMPLIED -- info on reason for change -- datetime %Datetime; #IMPLIED -- date and time of change -- >
The following elements are used to identify links to other parts of the body of the document, or to other files. Their use is explained in detail in Chapter 13.
<!--================== The Anchor Element ================================--> <!ENTITY % Shape "(rect|circle|poly|default)"> <!ENTITY % Coords "CDATA" -- comma separated list of numbers --> <!ELEMENT A - - (%inline;)* -(A) -- anchor --> <!ATTLIST A %attrs; -- %coreattrs, %i18n, %events -- charset %Charset; #IMPLIED -- char encoding of linked resource -- type %ContentType; #IMPLIED -- advisory content type -- name CDATA #IMPLIED -- named link end -- href %URL; #IMPLIED -- URL for linked resource -- hreflang %LanguageCode; #IMPLIED -- language code -- target %FrameTarget; #IMPLIED -- render in this frame -- rel %LinkTypes; #IMPLIED -- forward link types -- rev %LinkTypes; #IMPLIED -- reverse link types -- accesskey %Character; #IMPLIED -- accessibility key character -- shape %Shape; rect -- for use with OBJECT SHAPES -- coords %Coords; #IMPLIED -- for use with OBJECT SHAPES -- tabindex NUMBER #IMPLIED -- position in tabbing order -- onfocus %Script; #IMPLIED -- the element got the focus -- onblur %Script; #IMPLIED -- the element lost the focus -- >
<!--================== The LINK Element ==================================-->
<!--
Relationship values can be used in principle:
a) for document specific toolbars/menus when used
with the LINK element in document head e.g.
start, contents, previous, next, index, end, help
b) to link to a separate style sheet (rel=stylesheet)
c) to make a link to a script (rel=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 (rel=alternate media=print)
-->
<!ELEMENT LINK - O EMPTY -- a media-independent link -->
<!ATTLIST LINK
%attrs; -- %coreattrs, %i18n, %events --
charset %Charset; #IMPLIED -- char encoding of linked resource --
href %URL; #IMPLIED -- URL for linked resource --
hreflang %LanguageCode; #IMPLIED -- language code --
type %ContentType; #IMPLIED -- advisory content type --
rel %LinkTypes; #IMPLIED -- forward link types --
rev %LinkTypes; #IMPLIED -- reverse link types --
media %MediaDesc; #IMPLIED -- for rendering on these media --
target %FrameTarget; #IMPLIED -- render in this frame --
>
The following elements are used to identify images and the active hotspots (maps) that can be associated with them. Their use is explained in detail in Chapter 13.
<!--=================== Images ===========================================--> <!-- Length defined in strict DTD for cellpadding/cellspacing --> <!ENTITY % Length "CDATA" -- nn for pixels or nn% for percentage length --> <!ENTITY % MultiLength "CDATA" -- pixel, percentage, or relative --> <!ENTITY % MultiLengths "CDATA" -- comma-separated list of MultiLength --> <!ENTITY % Pixels "CDATA" -- integer representing length in pixels --> <!-- To avoid problems with text-only UAs as well as to make image content understandable and navigable to users of non-visual UAs, you need to provide a description with ALT, and avoid server-side image maps --> <!ELEMENT IMG - O EMPTY -- Embedded image --> <!ATTLIST IMG %attrs; -- %coreattrs, %i18n, %events -- src %URL; #REQUIRED -- URL of image to embed -- alt %Text; #REQUIRED -- short description -- longdesc %URL; #IMPLIED -- link to long description (complements alt) -- height %Length; #IMPLIED -- override height -- width %Length; #IMPLIED -- override width -- usemap %URL; #IMPLIED -- use client-side image map -- ismap (ismap) #IMPLIED -- use server-side 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 -->
<!--================== 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 -->
<!ELEMENT MAP - - (AREA)+ -- client-side image map -->
<!ATTLIST MAP
%attrs; -- %coreattrs, %i18n, %events --
name CDATA #REQUIRED -- name of image map for refs by usemap --
>
<!ELEMENT AREA - O EMPTY -- client-side image map area -->
<!ATTLIST AREA
%attrs; -- %coreattrs, %i18n, %events --
shape %Shape; rect -- controls interpretation of coords --
coords %Coords; #IMPLIED -- comma separated list of lengths --
href %URL; #IMPLIED -- URL for linked resource --
target %FrameTarget; #IMPLIED -- render in this frame --
nohref (nohref) #IMPLIED -- this region has no action --
alt %Text; #REQUIRED -- short description --
tabindex NUMBER #IMPLIED -- position in tabbing order --
accesskey %Character; #IMPLIED -- accessibility key character --
onfocus %Script; #IMPLIED -- the element got the focus --
onblur %Script; #IMPLIED -- the element lost the focus --
>
The following elements are used to identify where externally stored objects, such as movie and sound clips, or Java programs containing small pieces of application code (applets), are to be incorporated into a document. Their use is explained in detail in Chapter 13.
<!--==================== OBJECT ======================================-->
<!--
OBJECT is used to embed objects as part of HTML pages
PARAM elements should precede other content. SGML mixed content
model technicality precludes specifying this formally ...
-->
<!ELEMENT OBJECT - - (PARAM | %flow;)*
-- generic embedded object -->
<!ATTLIST OBJECT
%attrs; -- %coreattrs, %i18n, %events --
declare (declare) #IMPLIED -- declare but don't instantiate flag --
classid %URL; #IMPLIED -- identifies an implementation --
codebase %URL; #IMPLIED -- base URL for classid, data, archive --
data %URL; #IMPLIED -- reference to object's data --
type %ContentType; #IMPLIED -- content type for data --
codetype %ContentType; #IMPLIED -- content type for code --
archive %URL; #IMPLIED -- space separated archive list --
standby %Text; #IMPLIED -- message to show while loading --
height %Length; #IMPLIED -- override height --
width %Length; #IMPLIED -- override width --
usemap %URL; #IMPLIED -- use client-side image map --
shapes (shapes) #IMPLIED -- object has shaped hypertext links --
export (export) #IMPLIED -- export shapes to parent --
name CDATA #IMPLIED -- submit as part of form --
tabindex NUMBER #IMPLIED -- position in tabbing order --
%reserved; -- reserved for possible future use --
>
<!ELEMENT PARAM - O EMPTY -- named property value -->
<!ATTLIST PARAM
id ID #IMPLIED -- document-wide unique id --
name CDATA #REQUIRED -- property name --
value CDATA #IMPLIED -- property value --
valuetype (DATA|REF|OBJECT) DATA -- How to interpret value --
type %ContentType; #IMPLIED -- content type for value
when valuetype=ref --
>
The following elements provide the main text containers in the body of an HTML document. Their use is explained in detail in Chapter 13.
<!--=================== Paragraphs =======================================--> <!ELEMENT P - O (%inline;)* -- paragraph --> <!ATTLIST P %attrs; -- %coreattrs, %i18n, %events -- > <!--=================== Headings =========================================--> <!-- There are six levels of headings from H1 (the most important) to H6 (the least important). --> <!ELEMENT (%heading;) - - (%inline;)* -- heading --> <!ATTLIST (%heading;) %attrs; -- %coreattrs, %i18n, %events -- >
The following empty element can be used to insert rules between blocks of text:
<!--=================== Horizontal Rule ==================================--> <!ELEMENT HR - O EMPTY -- horizontal rule --> <!ATTLIST HR %coreattrs; -- id, class, style, title -- %events; >
Note: Quite why one would want to give a title or a unique identifier to a rule is somewhat unclear, as is how you could assign key-based events to rules.
The following element is used to identify pieces of preformatted text inserted into body of the document which should not have their text reformatted prior to display. Their use is explained in detail in Chapter 13.
<!--=================== Preformatted Text ================================--> <!-- excludes markup for images and changes in font size --> <!ENTITY % pre.exclusion "IMG|OBJECT|BIG|SMALL|SUB|SUP"> <!ELEMENT PRE - - (%inline;)* -(%pre.exclusion;) -- preformatted text --> <!ATTLIST PRE %attrs; -- %coreattrs, %i18n, %events -- >
Note particularly the use of the -(%pre-exclusion)
exception specification, to prevent
elements that would change the size of the fixed width characters typically used
to display preformatted text from occurring within it.
The following elements can be used to identify quoted text which is to be formatted either as an in-line piece of text or as a free-standing, typically indented, block of text:
<!--===================== Inline Quotes ==================================--> <!ELEMENT Q - - (%inline;)* -- short inline quotation --> <!ATTLIST Q %attrs; -- %coreattrs, %i18n, %events -- cite %URL; #IMPLIED -- URL for source document or msg -- > <!--=================== Block-like Quotes ================================--> <!ELEMENT BLOCKQUOTE - - (%block;|SCRIPT)+ -- long quotation --> <!ATTLIST BLOCKQUOTE %attrs; -- %coreattrs, %i18n, %events -- cite %URL; #IMPLIED -- URL for source document or msg -- >
Note particularly the optional cite attribute, which can be
used to store the URL of the document the text has been copied from.
The following elements are used to identify lists within the body of the document. Their use is explained in detail in Chapter 13.
<!--=================== Lists ============================================--> <!-- definition lists - DT for term, DD for its definition --> <!ELEMENT DL - - (DT|DD)+ -- definition list --> <!ATTLIST DL %attrs; -- %coreattrs, %i18n, %events -- > <!ELEMENT DT - O (%inline;)* -- definition term --> <!ELEMENT DD - O (%flow;)* -- definition description --> <!ATTLIST (DT|DD) %attrs; -- %coreattrs, %i18n, %events -- > <!ELEMENT OL - - (LI)+ -- ordered list --> <!ATTLIST OL %attrs; -- %coreattrs, %i18n, %events -- > <!-- Unordered Lists (UL) bullet styles --> <!ELEMENT UL - - (LI)+ -- unordered list --> <!ATTLIST UL %attrs; -- %coreattrs, %i18n, %events -- > <!ELEMENT LI - O (%flow;)* -- list item --> <!ATTLIST LI %attrs; -- %coreattrs, %i18n, %events -- >
Note that the only attributes assigned to lists and list items in this
strict version of the DTD are the standard attributes, including the class
and style attributes which replace the type and
compact attributes of earlier versions of HTML. Note also that
there is also now no method for specifying what number should be used for the
first item of an ordered list in the strict DTD.
Note: These now depracated attributes can be used if the transitional
version of the DTD (as defined inloose.dtd) is used.
The following elements are used to create data capture forms in the body of an HTML document. Their use is explained in detail in Chapter 14.
<!--================ Forms ===============================================-->
<!ELEMENT FORM - - (%block;|SCRIPT)+ -(FORM) -- interactive form -->
<!ATTLIST FORM
%attrs; -- %coreattrs, %i18n, %events --
action %URL; #REQUIRED -- server-side form handler --
method (GET|POST) GET -- HTTP method used to submit the form --
enctype %ContentType; "application/x-www-form-urlencoded"
onsubmit %Script; #IMPLIED -- the form was submitted --
onreset %Script; #IMPLIED -- the form was reset --
target %FrameTarget; #IMPLIED -- render in this frame --
accept-charset %Charsets; #IMPLIED -- list of supported charsets --
>
<!-- Each label must not contain more than ONE field -->
<!ELEMENT LABEL - - (%inline;)* -(LABEL) -- form field label text -->
<!ATTLIST LABEL
%attrs; -- %coreattrs, %i18n, %events --
for IDREF #IMPLIED -- matches field ID value --
accesskey %Character; #IMPLIED -- accessibility key character --
onfocus %Script; #IMPLIED -- the element got the focus --
onblur %Script; #IMPLIED -- the element lost the focus --
>
<!ENTITY % InputType
"(TEXT | PASSWORD | CHECKBOX |
RADIO | SUBMIT | RESET |
FILE | HIDDEN | IMAGE | BUTTON)"
>
<!-- attribute name required for all but submit & reset -->
<!ELEMENT INPUT - O EMPTY -- form control -->
<!ATTLIST INPUT
%attrs; -- %coreattrs, %i18n, %events --
type %InputType; TEXT -- what kind of widget is needed --
name CDATA #IMPLIED -- submit as part of form --
value CDATA #IMPLIED -- required for radio and checkboxes --
checked (checked) #IMPLIED -- for radio buttons and check boxes --
disabled (disabled) #IMPLIED -- control is unavailable in this context --
readonly (readonly) #IMPLIED -- for text and passwd --
size CDATA #IMPLIED -- specific to each type of field --
maxlength NUMBER #IMPLIED -- max chars for text fields --
src %URL; #IMPLIED -- for fields with images --
alt CDATA #IMPLIED -- short description --
usemap %URL; #IMPLIED -- use client-side image map --
tabindex NUMBER #IMPLIED -- position in tabbing order --
accesskey %Character; #IMPLIED -- accessibility key character --
onfocus %Script; #IMPLIED -- the element got the focus --
onblur %Script; #IMPLIED -- the element lost the focus --
onselect %Script; #IMPLIED -- some text was selected --
onchange %Script; #IMPLIED -- the element value was changed --
accept %ContentTypes; #IMPLIED -- list of MIME types for file upload --
%reserved; -- reserved for possible future use --
>
<!ELEMENT SELECT - - (OPTGROUP|OPTION)+ -- option selector -->
<!ATTLIST SELECT
%attrs; -- %coreattrs, %i18n, %events --
name CDATA #IMPLIED -- field name --
size NUMBER #IMPLIED -- rows visible --
multiple (multiple) #IMPLIED -- default is single selection --
disabled (disabled) #IMPLIED -- control is unavailable in this context --
tabindex NUMBER #IMPLIED -- position in tabbing order --
onfocus %Script; #IMPLIED -- the element got the focus --
onblur %Script; #IMPLIED -- the element lost the focus --
onchange %Script; #IMPLIED -- the element value was changed --
%reserved; -- reserved for possible future use --
>
<!ELEMENT OPTGROUP - - (OPTGROUP|OPTION)+ -- option group -->
<!ATTLIST OPTGROUP
%attrs; -- %coreattrs, %i18n, %events --
disabled (disabled) #IMPLIED -- control is unavailable in this context --
label %Text; #REQUIRED -- for use in hierarchical menus --
>
<!ELEMENT OPTION - O (#PCDATA) -- selectable choice -->
<!ATTLIST OPTION
%attrs; -- %coreattrs, %i18n, %events --
selected (selected) #IMPLIED
disabled (disabled) #IMPLIED -- control is unavailable in this context --
label %Text; #IMPLIED -- for use in hierarchical menus --
value CDATA #IMPLIED -- defaults to element content --
>
<!ELEMENT TEXTAREA - - (#PCDATA) -- multi-line text field -->
<!ATTLIST TEXTAREA
%attrs; -- %coreattrs, %i18n, %events --
name CDATA #IMPLIED
rows NUMBER #REQUIRED
cols NUMBER #REQUIRED
disabled (disabled) #IMPLIED -- control is unavailable in this context --
readonly (readonly) #IMPLIED
tabindex NUMBER #IMPLIED -- position in tabbing order --
onfocus %Script; #IMPLIED -- the element got the focus --
onblur %Script; #IMPLIED -- the element lost the focus --
onselect %Script; #IMPLIED -- some text was selected --
onchange %Script; #IMPLIED -- the element value was changed --
%reserved; -- reserved for possible future use --
>
<!--
#PCDATA is to solve the mixed content problem,
per specification only whitespace is allowed there!
-->
<!ELEMENT FIELDSET - - (#PCDATA,LEGEND,(%flow;)*) -- form control group -->
<!ATTLIST FIELDSET
%attrs; -- %coreattrs, %i18n, %events --
>
<!ELEMENT LEGEND - - (%inline;)* -- fieldset legend -->
<!ENTITY % LAlign "(top|bottom|left|right)">
<!ATTLIST LEGEND
%attrs; -- %coreattrs, %i18n, %events --
accesskey %Character; #IMPLIED -- accessibility key character --
>
<!ELEMENT BUTTON - -
(%flow;)* -(A|%formctrl;|FORM|FIELDSET)
-- push button -->
<!ATTLIST BUTTON
%attrs; -- %coreattrs, %i18n, %events --
name CDATA #IMPLIED -- for scripting/forms as submit button --
value CDATA #IMPLIED -- gets passed to server when submitted --
type (button|submit|reset) submit -- for use as form submit/reset button --
disabled (disabled) #IMPLIED -- control is unavailable in this context --
tabindex NUMBER #IMPLIED -- position in tabbing order --
accesskey %Character; #IMPLIED -- accessibility key character --
onfocus %Script; #IMPLIED -- the element got the focus --
onblur %Script; #IMPLIED -- the element lost the focus --
%reserved; -- reserved for possible future use --
>
The definition of the %InputType parameter entity is a good
example of how to simplify the structure of attribute definitions where long
lists of permitted values, which are likely to grow with time, are required. An
editor can make use of the current value of this parameter entity when creating
a pull-down option list for form creation.
The following elements are used to code tables in the body of an HTML document. Their use is explained in detail in Chapter 13. The formal specification for these elements is given in IETF RFC 1942.
<!--======================= Tables =======================================-->
<!-- IETF HTML table standard, see [RFC1942] -->
<!--
The BORDER attribute sets the thickness of the frame around the
table. The default units are screen pixels.
The FRAME attribute specifies which parts of the frame around
the table should be rendered. The values are not the same as
CALS to avoid a name clash with the VALIGN attribute.
The value "border" is included for backwards compatibility with
<TABLE BORDER> which yields frame=border and border=implied
For <TABLE BORDER=1> you get border=1 and frame=implied. In this
case, it is appropriate to treat this as frame=border for backwards
compatibility with deployed browsers.
-->
<!ENTITY % TFrame "(void|above|below|hsides|lhs|rhs|vsides|box|border)">
<!--
The RULES attribute defines which rules to draw between cells:
If RULES is absent then assume:
"none" if BORDER is absent or BORDER=0 otherwise "all"
-->
<!ENTITY % TRules "(none | groups | rows | cols | all)">
<!-- horizontal placement of table relative to document -->
<!ENTITY % TAlign "(left|center|right)">
<!-- horizontal alignment attributes for cell contents -->
<!ENTITY % cellhalign
"align (left|center|right|justify|char) #IMPLIED
char %Character; #IMPLIED -- alignment char, e.g. char=':' --
charoff %Length; #IMPLIED -- offset for alignment char --"
>
<!-- vertical alignment attributes for cell contents -->
<!ENTITY % cellvalign
"valign (top|middle|bottom|baseline) #IMPLIED"
>
<!ELEMENT TABLE - -
(CAPTION?, (COL*|COLGROUP*), THEAD?, TFOOT?, TBODY+)>
<!ELEMENT CAPTION - - (%inline;)* -- table caption -->
<!ELEMENT THEAD - O (TR)+ -- table header -->
<!ELEMENT TFOOT - O (TR)+ -- table footer -->
<!ELEMENT TBODY O O (TR)+ -- table body -->
<!ELEMENT COLGROUP - O (col)* -- table column group -->
<!ELEMENT COL - O EMPTY -- table column -->
<!ELEMENT TR - O (TH|TD)+ -- table row -->
<!ELEMENT (TH|TD) - O (%flow;)* -- table header cell, table data cell -->
<!ATTLIST TABLE -- table element --
%attrs; -- %coreattrs, %i18n, %events --
summary %Text; #IMPLIED -- purpose/structure for speech output --
width %Pixels; #IMPLIED -- table width relative to window --
border CDATA #IMPLIED -- controls frame width around table --
frame %TFrame; #IMPLIED -- which parts of table frame to include --
rules %TRules; #IMPLIED -- rulings between rows and cols --
cellspacing %Length; #IMPLIED -- spacing between cells --
cellpadding %Length; #IMPLIED -- spacing within cells --
%reserved; -- reserved for possible future use --
>
<!ENTITY % CAlign "(top|bottom|left|right)">
<!ATTLIST CAPTION
%attrs; -- %coreattrs, %i18n, %events --
>
<!--
COLGROUP groups a set of COL elements. It allows you to group
several semantically related columns together.
-->
<!ATTLIST COLGROUP
%attrs; -- %coreattrs, %i18n, %events --
span NUMBER 1 -- default number of columns in group --
width %MultiLength; #IMPLIED -- default width for enclosed COLs --
%cellhalign; -- horizontal alignment in cells --
%cellvalign; -- vertical alignment in cells --
>
<!--
COL elements define the alignment properties for cells in
one or more columns.
The WIDTH attribute specifies the width of the columns, e.g.
width=64 width in screen pixels
width=0.5* relative width of 0.5
The REPEAT attribute allows you to repeat the effects of
a COL element as if the same element was repeated n times.
There are no grouping semantics for repeated columns.
-->
<!ATTLIST COL -- column groups and properties --
%attrs; -- %coreattrs, %i18n, %events --
repeat NUMBER 1 -- repeat count for COL --
width %MultiLength; #IMPLIED -- column width specification --
%cellhalign; -- horizontal alignment in cells --
%cellvalign; -- vertical alignment in cells --
>
<!--
Use THEAD to duplicate headers when breaking table
across page boundaries, or for static headers when
TBODY sections are rendered in scrolling panel.
Use TFOOT to duplicate footers when breaking table
across page boundaries, or for static footers when
TBODY sections are rendered in scrolling panel.
Use multiple TBODY sections when rules are needed
between groups of table rows.
-->
<!ATTLIST (THEAD|TBODY|TFOOT) -- table section --
%attrs; -- %coreattrs, %i18n, %events --
%cellhalign; -- horizontal alignment in cells --
%cellvalign; -- vertical alignment in cells --
>
<!ATTLIST TR -- table row --
%attrs; -- %coreattrs, %i18n, %events --
%cellhalign; -- horizontal alignment in cells --
%cellvalign; -- vertical alignment in cells --
>
<!-- Scope is simpler than axes attribute for common tables -->
<!ENTITY % Scope "(row|col|rowgroup|colgroup)">
<!-- TH is for headers, TD for data, but for cells acting as both use TD -->
<!ATTLIST (TH|TD) -- header or data cell --
%attrs; -- %coreattrs, %i18n, %events --
abbr %Text; #IMPLIED -- abbreviation for header cell --
axis CDATA #IMPLIED -- names groups of related headers--
headers IDREFS #IMPLIED -- list of id's for header cells --
scope %Scope; #IMPLIED -- scope covered by header cells --
rowspan NUMBER 1 -- number of rows spanned by cell --
colspan NUMBER 1 -- number of cols spanned by cell --
%cellhalign; -- horizontal alignment in cells --
%cellvalign; -- vertical alignment in cells --
>
Note particularly that all elements except for one, the table body (<TBODY>)
element, are optional. This means that tables conforming to the simpler model
defined in Version 3.0 of HTML, which just consisted of a caption followed by a
number of table row (<TR>) elements, will still be valid
when used in conjunction with the extended definition.
The following elements can be used within HTML document headers to associate
meta-data with the text that forms the document body. Data stored within these
elements is not displayed in the text area of the screen, but can be displayed
in menus by browsers with a suitable user interface. Their use is explained in
detail in
Chapter 13. Note particularly the use of a
comment at the start of the section to remind readers that the parameter entity,
%head.misc, used to define an inclusion
for the header, was defined in an earlier part of the DTD.
<!--================ Document Head =======================================-->
<!-- %head.misc; defined earlier on as "SCRIPT | STYLE | META | LINK" -->
<!ENTITY % head.content "TITLE & BASE?">
<!ELEMENT HEAD O O (%head.content;) +(%head.misc;) -- document head -->
<!ATTLIST HEAD
%i18n; -- lang, dir --
profile %URL; #IMPLIED -- named dictionary of meta info --
>
<!-- 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. Exactly one title is required per document.
-->
<!ELEMENT TITLE - - (#PCDATA) -(%head.misc;) -- document title -->
<!ATTLIST TITLE %i18n>
<!ELEMENT BASE - O EMPTY -- document base URL -->
<!ATTLIST BASE
href %URL; #IMPLIED -- URL that acts as base URL --
target %FrameTarget; #IMPLIED -- render in this frame --
>
<!ELEMENT META - O EMPTY -- generic metainformation -->
<!ATTLIST META
%i18n; -- lang, dir, for use with content string --
http-equiv NAME #IMPLIED -- HTTP response header name --
name NAME #IMPLIED -- metainformation name --
content CDATA #REQUIRED -- associated information --
scheme CDATA #IMPLIED -- select form of content --
>
<!ELEMENT STYLE - - CDATA -- style info -->
<!ATTLIST STYLE
%i18n; -- lang, dir, for use with title --
type %ContentType; #REQUIRED -- content type of style language --
media %MediaDesc; #IMPLIED -- designed for use with these media --
title %Text; #IMPLIED -- advisory title --
>
<!ELEMENT SCRIPT - - CDATA -- script statements -->
<!ATTLIST SCRIPT
charset %Charset; #IMPLIED -- char encoding of linked resource --
type %ContentType; #REQUIRED -- content type of script language --
language CDATA #IMPLIED -- predefined script language name --
src %URL; #IMPLIED -- URL for an external script --
defer (defer) #IMPLIED -- UA may defer execution of script --
>
<!ELEMENT NOSCRIPT - - (%block;)+
-- alternate content container for non script-based rendering -->
<!ATTLIST NOSCRIPT
%attrs; -- %coreattrs, %i18n, %events --
>
The very last element to be defined in the HTML DTD is that for the
omissible <HTML> element.
<!--================ Document Structure ==================================--> <!ENTITY % version "version CDATA #FIXED '%HTML.Version;'"> <!ENTITY % html.content "HEAD, BODY"> <!ELEMENT HTML O O (%html.content;) -- document root element --> <!ATTLIST HTML %i18n; -- lang, dir -- >
Note: Although the %HTML.Version parameter entity is
used to assign a fixed default value
to the value of a version attribute in a parameter entity in this
segment of the DTD, there is no reference to this parameter entity in the strict
version of the DTD, so the attribute cannot be added to an HTML element, which
can only have the internationalization attributes associated with the %i18n;
parameter entity associated with it. This is because the use of this attribute
is now deprecated because it duplicates information in the public identifier
used to identify the document type definition in the immediately preceding
<!DOCTYPE declaration.
International Organization for Standardization (1991), Information Processing - 7-bit coded character set for information interchange (ISO 646:1991) Geneva: ISO.
International Organization for Standardization (1988), Data elements and interchange formats - Information interchange - Representation of dates and times (ISO 8601:1988) Geneva:ISO.
International Organization for Standardization (1986), Information Processing - Text and Office Systems - Standard Generalized Markup Language (SGML) (ISO 8879:1986) Geneva: ISO.
International Organization for Standardization (1993), Information technology - Universal Multiple-Octet Coded Character Set (UCS) (ISO 10646:1993) Geneva: ISO.
Internet Draft Proposal, Cascading Style Sheets (http://www.w3.org/pub/WWW/TR/WD-css1.html)
Internet RFC 1738, Uniform Resource Locators (URL) (http://ds.internic.net/rfc/rfc1738.txt)
Internet RFC 1766, Tags for the Identification of Languages (http://ds.internic.net/rfc/rfc1766.txt)
Internet RFC 1808, Relative Uniform Resource Locators (http://ds.internic.net/rfc/rfc1808.txt)
Internet RFC 1866, HyperText Markup Language - Version 2.0 (http://ds.internic.net/rfc/rfc1866.txt)
Internet RFC 1942, HTML Tables (http://ds.internic.net/rfc/rfc1942.txt)
Internet RFC 1945, Hypertext Transfer Protocol - HTTP/1.0 (http://ds.internic.net/rfc/rfc1945.txt)
Internet RFC 2045, Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies (http://ds.internic.net/rfc/rfc2045.txt)