XHTML" 1.0:
+XHTML™ 1.0:
The Extensible HyperText Markup Language
A Reformulation of HTML 4.0 in XML 1.0
@@ -70,7 +70,7 @@ http://www.w3.org/TR/1999/PR-xhtml1-19991210
(Postscript version,
PDF version,
ZIP archive, or
-Gzip'd TAR archive)
+Gzip'd TAR archive)
Latest version:
http://www.w3.org/TR/xhtml1 Previous versions:
http://www.w3.org/TR/1999/WD-xhtml1-19991124
@@ -85,28 +85,28 @@ use and soft
licensing rules apply.
Abstract
-This specification defines XHTML 1.0, a reformulation of HTML +
Abstract
+This specification defines XHTML 1.0, a reformulation of HTML 4.0 as an XML 1.0 application, and three DTDs corresponding to the ones defined by HTML 4.0. The semantics of the elements and their attributes are defined in the W3C Recommendation for HTML 4.0. These semantics provide the foundation for future extensibility of XHTML. Compatibility with existing HTML user agents is possible by following a small set of guidelines.
-Status of this document
-
- This section describes the status of this document at the time
+
+This section describes the status of this document at the time
of its publication. Other documents may supersede this document. The
latest status of this document series is maintained at the W3C.
- This specification is a Proposed Recommendation of the HTML Working Group. It is
+ This specification is a Proposed Recommendation of the HTML Working Group. It is
a revision of the Proposed Recommendation dated 24 August
1999 incorporating changes as a result of comments from the Proposed
Recommendation review, and
comments and further deliberations of the W3C HTML Working Group. A
diff-marked version from the previous
proposed recommendation is available for comparison purposes. On 10 December 1999, this document enters a
+ On 10 December 1999, this document enters a
Proposed Recommendation review period. From that date until 8 January
2000,
@@ -115,32 +115,32 @@ to review this specification and return comments in their completed
ballots to w3c-html-review@w3.org. Please send any comments of a
confidential nature in separate email to w3t-html@w3.org, which is
visible to the Team only. No sooner than 14 days after the end of the review period, the
-Director will announce the document's disposition: it may become a W3C
+ No sooner than 14 days after the end of the review period, the
+Director will announce the document's disposition: it may become a W3C
Recommendation (possibly with minor changes), it may revert to Working
Draft status, or it may be dropped as a W3C work item. Publication as a Proposed Recommendation does not imply endorsement
+ Publication as a Proposed Recommendation does not imply endorsement
by the W3C membership. This is still a draft document and may be
updated, replaced or obsoleted by other documents at any time. It is
inappropriate to cite W3C Proposed Recommendation as other than "work
in progress." This document has been produced as part of the W3C HTML Activity. The goals of
+ This document has been produced as part of the W3C HTML Activity. The goals of
the HTML Working
Group (members
only) are discussed in the HTML Working Group
charter (members
only). A list of current W3C Recommendations and other technical documents
+ A list of current W3C Recommendations and other technical documents
can be found at http://www.w3.org/TR. Public discussion on HTML features takes place on the mailing list www-html@w3.org (archive). The W3C
+ Public discussion on HTML features takes place on the mailing list www-html@w3.org (archive). The W3C
staff contact for work on HTML is Dave
Raggett. Please report errors in this document to www-html-editor@w3.org. The list of known errors in this specification is available at http://www.w3.org/1999/12/PR-xhtml1-19991210-errata. Please report errors in this document to www-html-editor@w3.org. The list of known errors in this specification is available at http://www.w3.org/1999/12/PR-xhtml1-19991210-errata. XHTML is a family of current and future document types and modules that
+ XHTML is a family of current and future document types and modules that
reproduce, subset, and extend HTML 4.0 [HTML]. XHTML family document types are XML based,
and ultimately are designed to work in conjunction with XML-based user agents.
The details of this family and its evolution are
discussed in more detail in the section on Future
Directions. XHTML 1.0 (this specification) is the first document type in the XHTML
+ XHTML 1.0 (this specification) is the first document type in the XHTML
family. It is a reformulation of the three HTML 4.0 document types as
applications of XML 1.0 [XML]. It is intended
to be used as a language for content that is both XML-conforming and, if some
simple guidelines are followed,
operates in HTML 4.0 conforming user agents. Developers who migrate
their content to XHTML 1.0 will realize the following benefits: The XHTML family is the next step in the evolution of the Internet. By
+ The XHTML family is the next step in the evolution of the Internet. By
migrating to XHTML today, content developers can enter the XML world with all
of its attendant benefits, while still remaining confident in their
-content's backward and future compatibility. HTML 4.0 [HTML] is an SGML (Standard
+content's backward and future compatibility. HTML 4.0 [HTML] is an SGML (Standard
Generalized Markup Language) application conforming to
International Standard ISO 8879, and is widely regarded as the
standard publishing language of the World Wide Web. SGML is a language for describing markup languages,
+ SGML is a language for describing markup languages,
particularly those used in electronic document exchange, document
management, and document publishing. HTML is an example of a
language defined in SGML. SGML has been around since the middle 1980's and has remained
+ SGML has been around since the middle 1980's and has remained
quite stable. Much of this stability stems from the fact that the
language is both feature-rich and flexible. This flexibility,
however, comes at a price, and that price is a level of
complexity that has inhibited its adoption in a diversity of
environments, including the World Wide Web. HTML, as originally conceived, was to be a language for the
+ HTML, as originally conceived, was to be a language for the
exchange of scientific and other technical documents, suitable
for use by non-document specialists. HTML addressed the problem
of SGML complexity by specifying a small set of structural and
@@ -220,36 +220,36 @@ semantic tags suitable for authoring relatively simple documents.
In addition to simplifying the document structure, HTML added
support for hypertext. Multimedia capabilities were added
later. In a remarkably short space of time, HTML became wildly
-popular and rapidly outgrew its original purpose. Since HTML's
+ In a remarkably short space of time, HTML became wildly
+popular and rapidly outgrew its original purpose. Since HTML's
inception, there has been rapid invention of new elements for use
within HTML (as a standard) and for adapting HTML to vertical,
highly specialized, markets. This plethora of new elements has
led to compatibility problems for documents across different
platforms. As the heterogeneity of both software and platforms rapidly
-proliferate, it is clear that the suitability of 'classic' HTML
+ As the heterogeneity of both software and platforms rapidly
+proliferate, it is clear that the suitability of 'classic' HTML
4.0 for use on these platforms is somewhat limited. XML" is the shorthand for Extensible Markup
+ XML™ is the shorthand for Extensible Markup
Language, and is an acronym of Extensible Markup Language [XML]. XML was conceived as a means of regaining the power and
+ XML was conceived as a means of regaining the power and
flexibility of SGML without most of its complexity. Although a
-restricted form of SGML, XML nonetheless preserves most of SGML's
-power and richness, and yet still retains all of SGML's commonly
+restricted form of SGML, XML nonetheless preserves most of SGML's
+power and richness, and yet still retains all of SGML's commonly
used features. While retaining these beneficial features, XML removes many of
+ While retaining these beneficial features, XML removes many of
the more complex features of SGML that make the authoring and
design of suitable software both difficult and costly. The benefits of migrating to XHTML 1.0 are described above. Some of the
+ The benefits of migrating to XHTML 1.0 are described above. Some of the
benefits of migrating to XHTML in general are: The following terms are used in this specification. These
+ The following terms are used in this specification. These
terms extend the definitions in
[RFC2119] in ways based upon similar definitions in ISO/IEC
9945-1:1990 [POSIX.1]: This version of XHTML provides a definition of strictly
+
+ This version of XHTML provides a definition of strictly
conforming XHTML documents, which are restricted to tags and
attributes from the XHTML namespace. See Section 3.1.2 for information on using XHTML
with other namespaces, for instance, to include metadata
expressed in RDF within XHTML documents. A Strictly Conforming XHTML Document is a document that
+ A Strictly Conforming XHTML Document is a document that
requires only the facilities described as mandatory in this
specification. Such a document must meet all of the following
criteria: It must validate against one of the three DTDs found in Appendix A. It must validate against one of the three DTDs found in Appendix A. The root element of the document must be The root element of the document must designate the XHTML
namespace using the There must be a DOCTYPE declaration in the document prior to
the root element. The public identifier included in
the DOCTYPE declaration must reference one of the three DTDs
-found in Appendix A using the respective
+found in Appendix A using the respective
Formal Public Identifier. The system identifier may be changed to reflect
local system conventions. Here is an example of a minimal XHTML document. Here is an example of a minimal XHTML document. Note that in this example, the XML declaration is included. An XML
+ Note that in this example, the XML declaration is included. An XML
declaration like the one above is
not required in all XML documents. XHTML document authors are strongly encouraged to use XML declarations in all their documents. Such a declaration is required
when the character encoding of the document is other than the default UTF-8 or
UTF-16. The XHTML namespace may be used with other XML namespaces
+ The XHTML namespace may be used with other XML namespaces
as per [XMLNAMES], although such
documents are not strictly conforming XHTML 1.0 documents as
defined above. Future work by W3C will address ways to specify
conformance for documents involving multiple namespaces. The following example shows the way in which XHTML 1.0 could
+ The following example shows the way in which XHTML 1.0 could
be used in conjunction with the MathML Recommendation: The following example shows the way in which XHTML 1.0 markup
+ The following example shows the way in which XHTML 1.0 markup
could be incorporated into another XML namespace: A conforming user agent must meet all of the following
+ A conforming user agent must meet all of the following
criteria:
-The XML processor normalizes different system's line end codes into one
+The XML processor normalizes different system's line end codes into one
single line-feed character, that is passed up to the application. The XHTML
user agent in addition, must treat the following characters as whitespace:
-In elements where the 'xml:space' attribute is set to 'preserve', the user
+In elements where the 'xml:space' attribute is set to 'preserve', the user
agent must leave all whitespace characters intact (with the exception of
leading and trailing whitespace characters, which should be removed).
Otherwise, whitespace
@@ -582,10 +582,10 @@ space characters.
Whitespace in attribute values is processed according to [XML]. Due to the fact that XHTML is an XML application, certain
+ Due to the fact that XHTML is an XML application, certain
practices that were perfectly legal in SGML-based HTML 4.0 [HTML] must be changed. Well-formedness is a new concept
+ Well-formedness is a new concept
introduced by [XML]. Essentially this
means that all elements must either have closing tags or be
written in a special form (as described below), and that all the
elements must nest. Although overlapping is illegal in SGML, it was widely
+ Although overlapping is illegal in SGML, it was widely
tolerated in existing browsers. CORRECT: nested elements. <p>here is an emphasized
<em>paragraph</em>.</p> INCORRECT: overlapping elements <p>here is an emphasized
<em>paragraph.</p></em> XHTML documents must use lower case for all HTML element and
+ XHTML documents must use lower case for all HTML element and
attribute names. This difference is necessary because XML is
case-sensitive e.g. <li> and <LI> are different
tags. In SGML-based HTML 4.0 certain elements were permitted to omit
+ In SGML-based HTML 4.0 certain elements were permitted to omit
the end tag; with the elements that followed implying closure.
This omission is not permitted in XML-based XHTML. All elements
other than those declared in the DTD as CORRECT: terminated elements <p>here is a paragraph.</p><p>here is
another paragraph.</p> INCORRECT: unterminated elements <p>here is a paragraph.<p>here is another
paragraph. All attribute values must be quoted, even those which appear
+ All attribute values must be quoted, even those which appear
to be numeric. CORRECT: quoted attribute values <table rows="3"> INCORRECT: unquoted attribute values <table rows=3> XML does not support attribute minimization. Attribute-value
+ XML does not support attribute minimization. Attribute-value
pairs must be written in full. Attribute names such as CORRECT: unminimized attributes <dl compact="compact"> INCORRECT: minimized attributes <dl compact> Empty elements must either have an end tag or the start tag must end with Empty elements must either have an end tag or the start tag must end with CORRECT: terminated empty tags <br/><hr/> INCORRECT: unterminated empty tags <br><hr> In attribute values, user agents will strip leading and
+ In attribute values, user agents will strip leading and
trailing whitespace from attribute values and map sequences
of one or more whitespace characters (including line breaks) to
a single inter-word space (an ASCII space character for western
scripts). See
Section 3.3.3 of [XML]. In XHTML, the script and style elements are declared as having
+ In XHTML, the script and style elements are declared as having
An alternative is to use external script and style
+ An alternative is to use external script and style
documents. SGML gives the writer of a DTD the ability to exclude specific
+ SGML gives the writer of a DTD the ability to exclude specific
elements from being contained within an element. Such
prohibitions (called "exclusions") are not possible in XML. For example, the HTML 4.0 Strict DTD forbids the nesting of an
-' For example, the HTML 4.0 Strict DTD forbids the nesting of an
+' HTML 4.0 defined the HTML 4.0 defined the In XML, fragment identifiers are of type In XML, fragment identifiers are of type Note that in XHTML 1.0, the Note that in XHTML 1.0, the Although there is no requirement for XHTML 1.0 documents to be
+ Although there is no requirement for XHTML 1.0 documents to be
compatible with existing user agents, in practice this is easy to
accomplish. Guidelines for creating compatible documents can be
-found in Appendix C. As of the publication of this recommendation, the general
+found in Appendix C. As of the publication of this recommendation, the general
recommended MIME labeling for XML-based applications
has yet to be resolved. However, XHTML Documents which follow the guidelines set forth
+ However, XHTML Documents which follow the guidelines set forth
in Appendix C, "HTML Compatibility Guidelines" may be
labeled with the Internet Media Type "text/html", as they
are compatible with most HTML browsers. This document
makes no recommendation about MIME labeling of other
XHTML documents. XHTML 1.0 provides the basis for a family of document types
+ XHTML 1.0 provides the basis for a family of document types
that will extend and subset XHTML, in order to support a wide
range of new devices and applications, by defining modules and
specifying a mechanism for combining these modules. This
mechanism will enable the extension and sub-setting of XHTML 1.0
in a uniform way through the definition of new modules. As the use of XHTML moves from the traditional desktop user
+ As the use of XHTML moves from the traditional desktop user
agents to other platforms, it is clear that not all of the XHTML
elements will be required on all platforms. For example a hand
held device or a cell-phone may only support a subset of XHTML
elements. The process of modularization breaks XHTML up into a series of
+ The process of modularization breaks XHTML up into a series of
smaller element sets. These elements can then be recombined to
meet the needs of different communities. These modules will be defined in a later W3C document. These modules will be defined in a later W3C document. Modularization brings with it several advantages: Modularization brings with it several advantages: It provides a formal mechanism for sub-setting XHTML. It provides a formal mechanism for extending XHTML. It simplifies the transformation between document types. It promotes the reuse of modules in new document types. A document profile specifies the syntax and semantics of a set
+ A document profile specifies the syntax and semantics of a set
of documents. Conformance to a document profile provides a basis
for interoperability guarantees. The document profile specifies
the facilities required to process documents of that type, e.g.
which image formats can be used, levels of scripting, style sheet
support, and so on. For product designers this enables various groups to define
+ For product designers this enables various groups to define
their own standard profile. For authors this will obviate the need to write several
+ For authors this will obviate the need to write several
different versions of documents for different clients. For special groups such as chemists, medical doctors, or
+ For special groups such as chemists, medical doctors, or
mathematicians this allows a special profile to be built using
standard HTML elements plus a group of elements geared to the
-specialist's needs.
- This appendix is normative.
- These DTDs and entity sets form a normative part of this
+
+This appendix is normative.
+ These DTDs and entity sets form a normative part of this
specification. The complete set of DTD files together with an XML
declaration and SGML Open Catalog is included in the zip file for this specification. These DTDs approximate the HTML 4.0 DTDs. It is likely that
+ These DTDs approximate the HTML 4.0 DTDs. It is likely that
when the DTDs are modularized, a method of DTD construction will
be employed that corresponds more closely to HTML 4.0. The XHTML entity sets are the same as for HTML 4.0, but have
+ The XHTML entity sets are the same as for HTML 4.0, but have
been modified to be valid XML 1.0 entity declarations. Note the
entity for the Euro currency sign (
- This appendix is normative.
- The following elements have prohibitions on which elements
+
+This appendix is normative.
+ The following elements have prohibitions on which elements
they can contain (see Section 4.9). This
prohibition applies to all depths of nesting, i.e. it contains
all the descendant elements.
- This appendix is informative.
- This appendix summarizes design guidelines for authors who
+
+This appendix is informative.
+ This appendix summarizes design guidelines for authors who
wish their XHTML documents to render on existing HTML user
agents. Be aware that processing instructions are rendered on some
+ Be aware that processing instructions are rendered on some
user agents. However, also note that when the XML declaration is not included
in a document, the document can only use the default character encodings UTF-8
or UTF-16. Include a space before the trailing Include a space before the trailing Given an empty instance of an element whose content model is
+ Given an empty instance of an element whose content model is
not Use external style sheets if your style sheet uses Use external style sheets if your style sheet uses Avoid line breaks and multiple whitespace characters within
+ Avoid line breaks and multiple whitespace characters within
attribute values. These are handled inconsistently by user
agents. Don't include more than one Don't include more than one Use both the Use both the In XML, URIs [RFC2396] that end with fragment identifiers of the form
+ In XML, URIs [RFC2396] that end with fragment identifiers of the form
Further, since the set of
+ Further, since the set of
legal values for attributes of type Finally, note that XHTML 1.0 has deprecated the
+ Finally, note that XHTML 1.0 has deprecated the
To specify a character encoding in the document, use both the
+ To specify a character encoding in the document, use both the
encoding attribute specification on the xml declaration (e.g.
Some HTML user agents are unable to interpret boolean
+ Some HTML user agents are unable to interpret boolean
attributes when these appear in their full (non-minimized) form,
-as required by XML 1.0. Note this problem doesn't effect user
+as required by XML 1.0. Note this problem doesn't effect user
agents compliant with HTML 4.0. The following attributes are
involved:
+
The Document Object Model level 1 Recommendation [DOM]
defines document object model interfaces for XML and HTML 4.0. The HTML 4.0
document object model specifies that HTML element and attribute names are
@@ -1068,13 +1068,13 @@ element and attribute names are returned in the case they are specified. In
XHTML 1.0, elements and attributes are specified in lower-case. This apparent difference can be
addressed in two ways:
+
When an attribute value contains an ampersand, it must be expressed as a character
entity reference
(e.g. " The Cascading Style Sheets level 2 Recommendation [CSS2] defines style
+ The Cascading Style Sheets level 2 Recommendation [CSS2] defines style
properties which are applied to the parse tree of the HTML or XML
document. Differences in parsing will produce different visual or
aural results, depending on the selectors used. The following hints
will reduce this effect for documents which are served without
modification as both media types:
- This appendix is informative.
- This specification was written with the participation of the
+
+This appendix is informative.
+ This specification was written with the participation of the
members of the W3C HTML working group:
- This appendix is informative.
-
+This appendix is informative.
+
-
+
+
Status of this document
+
- Contents
-
-
+Contents
+
+
- 1. What is XHTML?
-
-
+1. What is XHTML?
+
+
-
+
+
-
- 1.1 What is HTML 4.0?
-
-
+1.1 What is HTML 4.0?
+
+
- 1.2 What is XML?
-
-
+1.2 What is XML?
+
+
- 1.3 Why the need for XHTML?
-
-
+1.3 Why the need for XHTML?
+
+
-
-
+
+
- 2. Definitions
-
-
- 2.1 Terminology
-
-
+2. Definitions
+
+
+2.1 Terminology
+
+
-
-
+
-
- 2.2 General Terms
-
-
-
+
+2.2 General Terms
+
+
+
+
- 3. Normative Definition of
+
+
+3. Normative Definition of
XHTML 1.0
-
-
- 3.1 Document
+
+3.1 Document
Conformance
-
-
- 3.1.1 Strictly Conforming
+
+
+3.1.1 Strictly Conforming
Documents
-
-
-
+
-
<html>.xmlns attribute [XMLNAMES]. The namespace for XHTML is
defined to be
http://www.w3.org/1999/xhtml.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
@@ -461,23 +461,23 @@ local system conventions.
</body>
</html>
- 3.1.2 Using XHTML with
+
+
+3.1.2 Using XHTML with
other namespaces
-
-
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
@@ -497,68 +497,68 @@ be used in conjunction with the MathML Recommendation:
</html>
<?xml version="1.0" encoding="UTF-8"?>
<!-- initially, the default namespace is "books" -->
-<book xmlns='urn:loc.gov:books'
- xmlns:isbn='urn:ISBN:0-395-36341-6' xml:lang="en" lang="en">
+<book xmlns='urn:loc.gov:books'
+ xmlns:isbn='urn:ISBN:0-395-36341-6' xml:lang="en" lang="en">
<title>Cheaper by the Dozen</title>
<isbn:number>1568491379</isbn:number>
<notes>
<!-- make HTML the default namespace for a hypertext commentary -->
- <p xmlns='http://www.w3.org/1999/xhtml'>
+ <p xmlns='http://www.w3.org/1999/xhtml'>
This is also available <a href="http://www.w3.org/">online</a>.
</p>
</notes>
</book>
- 3.2 User Agent
+
+
+3.2 User Agent
Conformance
-
-
-
-
+
+ID (e.g. the id attribute on most XHTML elements)
as fragment identifiers.
- 4. Differences with HTML
+
+
+4. Differences with HTML
4.0
-
-
- 4.1 Documents must be
+
+
+4.1 Documents must be
well-formed
-
-
- 4.2 Element and attribute
+
+
+4.2 Element and attribute
names must be in lower case
-
-
- 4.3 For non-empty elements,
+
+
+4.3 For non-empty elements,
end tags are required
-
- EMPTY must
have an end tag.
- 4.4 Attribute values must
+
+
+4.4 Attribute values must
always be quoted
-
-
- 4.5 Attribute
+
+
+4.5 Attribute
Minimization
-
-
compact and checked cannot occur in elements
without their value being specified.
- 4.6 Empty Elements
-
- />. For instance,
+
+4.6 Empty Elements
+
+/>. For instance,
<br/> or <hr></hr>. See HTML Compatibility Guidelines for information on ways to
ensure this is backward compatible with HTML 4.0 user agents.
- 4.7 Whitespace handling in
+
+
+4.7 Whitespace handling in
attribute values
-
-
- 4.8 Script and Style
+
+
+4.8 Script and Style
elements
-
- #PCDATA content. As a result, < and
& will be treated as the start of markup, and
entities such as < and &
@@ -739,7 +739,7 @@ will be recognized as entity references by the XML processor to
the content of the script or style element within a
CDATA marked section avoids the expansion of these
entities.
<script>
<![CDATA[
@@ -748,38 +748,38 @@ entities.
</script>
CDATA sections are recognized by the XML
+CDATA sections are recognized by the XML
processor and appear as nodes in the Document Object Model, see
Section 1.3 of the DOM Level 1 Recommendation [DOM].
- 4.9 SGML exclusions
-
-
+4.9 SGML exclusions
+
+a' element within another 'a' element
+a' element within another 'a' element
to any descendant depth. It is not possible to spell out such
prohibitions in XML. Even though these prohibitions cannot be
defined in the DTD, certain elements should not be nested. A
summary of such elements and the elements that should not be
nested in them is found in the normative
-Appendix B.
- 4.10 The elements with 'id' and 'name'
+Appendix B.
+
+4.10 The elements with 'id' and 'name'
attributes
-
- name attribute for the elements
+
+name attribute for the elements
a,
applet, frame,
iframe, img, and map.
HTML 4.0 also introduced
the id attribute. Both of these attributes are designed to be
used as fragment identifiers.ID, and
+ID, and
there can only be a single attribute of type ID per element.
Therefore, in XHTML 1.0 the id
attribute is defined to be of type ID. In order to
@@ -791,209 +791,209 @@ See the HTML Compatibility
Guidelines for information on ensuring such anchors are backwards
compatible when serving XHTML documents as media type text/html.
name attribute of these
+name attribute of these
elements is formally deprecated, and will be removed in a
subsequent version of XHTML.
- 5. Compatibility Issues
-
-
+5. Compatibility Issues
+
+
- 5.1 Internet Media Type
-
-
+5.1 Internet Media Type
+
+
- 6. Future Directions
-
-
+6. Future Directions
+
+
- 6.1 Modularizing HTML
-
-
+6.1 Modularizing HTML
+
+
- 6.2 Subsets and
+
+
+6.2 Subsets and
Extensibility
-
-
-
+
-
- 6.3 Document
+
+
+
+6.3 Document
Profiles
-
-
+
Appendix A. DTDs
-
- A.1 Document Type
+
+
+A.1 Document Type
Definitions
-
-
-
+
+
-
- A.2 Entity Sets
-
-
+A.2 Entity Sets
+
+€ or
€ or €) is defined
as part of the special characters.
-
-
+
+
- Appendix B. Element
+
+
+Appendix B. Element
Prohibitions
-
-
-
- a
-
+
+a
+a elements.pre
- img, object,
+pre
+img, object,
big, small, sub, or
sup elements.button
- input, select,
+button
+input, select,
textarea, label, button,
form, fieldset, iframe or
isindex elements.label
- label elements.form
- form elements.label
+label elements.form
+form elements.
- Appendix C.
+
+
+Appendix C.
HTML Compatibility Guidelines
-
- C.1 Processing Instructions
- C.1 Processing Instructions
+C.2 Empty Elements
- / and
+, C.2 Empty Elements
+/ and
> of empty elements, e.g.
-<br />,
-<hr /> and <img
-src="karen.jpg" alt="Karen" />. Also, use the
+<br />
+<hr /> and <img
+src="karen.jpg" alt="Karen" />. Also, use the
minimized tag syntax for empty elements, e.g. <br />, as the alternative syntax <br></br> allowed by XML
gives uncertain results in many existing user agents.C.3 Element Minimization and Empty Element Content
- C.3 Element Minimization and Empty Element Content
+EMPTY (for example, an empty title or paragraph)
do not use the minimized form (e.g. use
<p> </p> and not
-<p />).C.4 Embedded Style Sheets and Scripts
-
+<p />).C.4 Embedded Style Sheets and Scripts
+
< or & or ]]> or --. Use
external scripts if your script uses < or
& or ]]> or --. Note that XML parsers
@@ -1001,28 +1001,28 @@ are permitted to silently remove the contents of comments. Therefore, the histor
practice of "hiding" scripts and style sheets within comments to make the
documents backward compatible is likely to not work as expected in XML-based
implementations.C.5 Line Breaks within Attribute Values
- C.5 Line Breaks within Attribute Values
+C.6 Isindex
- isindex element in
+C.6 Isindex
+isindex element in
the document head. The isindex element
is deprecated in favor of the input element.C.7 The
- lang and xml:lang Attributeslang and xml:lang
+C.7 The
+lang and xml:lang Attributeslang and xml:lang
attributes when specifying the language of an element. The value
of the xml:lang attribute takes precedence.C.8 Fragment Identifiers
- C.8 Fragment Identifiers
+"#foo" do not refer to elements with an attribute
name="foo"; rather, they refer to elements with an
attribute defined to be of type ID, e.g., the
-id attribute in HTML 4.0. Many existing HTML clients don't
+id attribute in HTML 4.0. Many existing HTML clients don't
support the use of ID-type attributes in this way,
so identical values may be supplied for both of these attributes to ensure
maximum forward and backward compatibility (e.g., <a id="foo" name="foo">...</a>).ID is much smaller than
for those of type CDATA, the type of the name
attribute has been changed to NMTOKEN. This attribute is
@@ -1035,31 +1035,31 @@ must be unique within the document, valid, and any references to these
fragment identifiers (both
internal and external) must be updated should the values be changed during
conversion.name attribute of the a, applet, frame, iframe, img, and map
elements, and it will be
removed from XHTML in subsequent versions.C.9 Character Encoding
- C.9 Character Encoding
+<?xml version="1.0"
encoding="EUC-JP"?>) and a meta http-equiv statement
(e.g. <meta http-equiv="Content-type"
-content='text/html; charset="EUC-JP"' />). The
+content='text/html; charset="EUC-JP"' />). The
value of the encoding attribute of the xml processing instruction
takes precedence.C.10 Boolean Attributes
- C.10 Boolean Attributes
+compact, nowrap,
ismap, declare, noshade,
checked, disabled, readonly,
multiple, selected,
noresize, defer.C.11 Document Object Model and XHTML
- C.11 Document Object Model and XHTML
+
-
+
+
- text/html
via the DOM can use the HTML DOM,
and can rely upon element and attribute names being returned in
upper-case from those interfaces.text/xml or application/xml
can also use the XML DOM. Elements and attributes will be returned in lower-case.
Also, some XHTML elements may or may
@@ -1088,9 +1088,9 @@ This is not possible in XML. Rather than require document authors to insert
extraneous elements, XHTML has made the elements optional.
Applications need to adapt to this
accordingly.C.12 Using Ampersands in Attribute Values
- C.12 Using Ampersands in Attribute Values
+&"). For example, when the
@@ -1101,46 +1101,46 @@ CGI script that takes parameters, it must be expressed as
rather than as
http://my.site.dom/cgi-bin/myscript.pl?class=guest&name=user.
C.13 Cascading Style Sheets (CSS) and XHTML
- C.13 Cascading Style Sheets (CSS) and XHTML
+
-
-
+
+
- Appendix D.
+
+
+Appendix D.
Acknowledgements
-
-
-
-
+
+
+
Murray Altheim, Sun Microsystems
Daniel Austin, CNET: The Computer Network
Frank Boumphrey, HTML Writers Guild
@@ -1153,7 +1153,7 @@ Masayasu Ishikawa, W3C
Warner ten Kate, Philips Electronics
Peter King, Phone.com
Paula Klante, JetForm
-Shin'ichi Matsui, W3C/Panasonic
+Shin'ichi Matsui, W3C/Panasonic
Shane McCarron, Applied Testing and Technology (The Open Group through August
1999)
Ann Navarro, HTML Writers Guild
@@ -1164,124 +1164,124 @@ Sebastian Schnitzenbaumer, Stack Overflow
Chris Wilson, Microsoft
Ted Wugofski, Gateway 2000
Dan Zigmond, WebTV Networks
- Appendix E. References
-
-
-
+
+Appendix E. References
+
+
+
-
Available at:
http://www.w3.org/TR/REC-CSS2
Available at:
http://www.w3.org/TR/REC-DOM-Level-1
Available at:
http://www.w3.org/TR/1999/PR-html40-19990824
Available at
http://www.ietf.org/rfc/rfc2046.txt. Note that this RFC
obsoletes RFC1521, RFC1522, and RFC1590.
Available at:
http://www.ietf.org/rfc/rfc2119.txt
Available at:
http://www.ietf.org/rfc/rfc2376.txt
This document updates RFC1738 and RFC1808.
Available at:
http://www.ietf.org/rfc/rfc2396.txt
Available at:
http://www.w3.org/TR/REC-xml
XML namespaces provide a simple method for qualifying names used
in XML documents by associating them with namespaces identified
by URI.
Available at:
http://www.w3.org/TR/REC-xml-names
-