The XHTML
Basic document type includes the minimal set of modules required to be
an XHTML
host language document type, and in addition it includes images, forms,
basic tables, and object support.
It is designed for Web clients that do not support the full set of
XHTML
features; for example, Web clients such as mobile phones,
PDAs,
pagers, and settop boxes. The document type is rich enough for
content authoring.
XHTML
Basic is designed as a common base that may be extended. For example,
an event module that is more generic than the traditional HTML 4 event system could
be added or it could be extended by additional modules from XHTML
Modularization such as the Scripting Module. The goal of
XHTML
Basic is to serve as a common language supported by various kinds of
user agents.
The document type definition is implemented using
XHTML
modules as defined in "Modularization of
XHTML"
[XHTMLMOD].
Status of this Document
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 document has been reviewed by
W3C Members and other
interested parties and has been endorsed by the Director as a
W3C Recommendation.
It is a stable document and may be used as reference material or cited
as a normative reference from another document.
W3C's role
in making the Recommendation is to draw attention to the specification
and to promote its widespread deployment.
This enhances the functionality and interoperability of the Web.
This document has been produced by the
W3C HTML Working Group
(members
only) as part of the W3C HTML Activity.
It integrates feedback from the WAP Forum
and members of the W3C Mobile Access Interest
Group (members
only). This document will be used by
the W3C
HTML Working Group
and the W3C Mobile
Access Interest Group to find a common ground for future markup languages
aimed at content for small information appliances.
"Modularization of XHTML"
[XHTMLMOD] defines the XHTML modules
used in the XHTML Basic document type. At the time of this publication, the
Candidate Recommendation review period for "Modularization of
XHTML" has
closed. Based on that review, the W3C HTML
Working Group believes that the definition of modules used in XHTML Basic is
stable, and the Working Group does not expect to make changes to
"Modularization of XHTML" that would be incompatible with XHTML Basic.
Please report errors in this document to
www-html-editor@w3.org (archive).
The list of known errors in this document is available at
http://www.w3.org/2000/12/REC-xhtml-basic-20001219-errata.
The English version of this specification is the only normative version.
Information about translations
of this document is available at http://www.w3.org/MarkUp/translations.
A list of current W3C
Recommendations and other technical documents can be found at
http://www.w3.org/TR.
HTML 4 is
a powerful language for authoring Web content, but its design does not
take into consideration issues
pertinent to small devices, including the implementation cost (in
power, memory, etc.)
of the full feature set.
Consumer devices with limited resources cannot generally afford to
implement the full feature set of
HTML 4.
Requiring a full-fledged computer for access to the
World Wide Web excludes a large portion of the population from
consumer device access of online information and services.
Because there are many ways to subset
HTML, there are
many almost identical subsets defined by organizations and companies.
Without a common base set of features, developing applications for
a wide range of Web clients is difficult.
The motivation for XHTML Basic is to provide an XHTML
document type that can be shared across communities
(e.g. desktop,
TV, and mobile phones), and that is
rich enough to be used for simple content authoring. New community-wide
document types can be defined by extending XHTML Basic in
such a way that XHTML Basic documents are in the set of valid documents of
the new document type. Thus an XHTML Basic
document can be presented on the maximum number of Web clients.
The document type definition for XHTML Basic is
implemented based on the XHTML modules
defined in Modularization of XHTML
[XHTMLMOD].
1.2. Background and Requirements
Information appliances are targeted for particular uses. They support
the features they need for the functions they are designed to fulfill.
The following are examples of different information appliances:
Mobile phones
Televisions
PDAs
Vending machines
Pagers
Car navigation systems
Mobile game machines
Digital book readers
Smart watches
Existing subsets and variants of HTML for these clients include
Compact HTML
[CHTML], the Wireless Markup Language
[WML], and the "HTML 4.0 Guidelines for
Mobile Access" [GUIDELINES].
The common features found in these document types include:
Basic text (including headings, paragraphs, and lists)
Hyperlinks and links to related documents
Basic forms
Basic tables
Images
Meta information
This set of HTML
features has been the starting point for the design of XHTML Basic.
Since many content developers are familiar with these
HTML features,
they comprise a useful host language that may be combined with
markup modules from other languages according to the methods described in
"Modularization of
XHTML"
[XHTMLMOD]. For example, XHTML Basic may
be extended with an event module that is more generic than the traditional
HTML 4 event system
or it could be extended by additional modules from XHTML
Modularization such as the Scripting Module.
It is not the intention of XHTML Basic to
limit the functionality of future languages. But since the features
in HTML 4 (frames,
advanced tables, a fixed set of attribute event handlers, etc.) were developed for a desktop computer type
of client, they have proved to be inappropriate for many non-desktop devices.
XHTML
Basic will be extended and built upon.
Extending XHTML
from a common and basic set of features, instead of almost identical subsets
or the too-large set of functions in HTML 4, will be good for
interoperability on the Web, as well as for scalability.
Compared to the rich functionality of HTML 4, XHTML Basic
may look like one step back, but in fact, it is two steps forward for
clients that do not need what is in HTML 4 and for content
developers who get one XHTML subset
instead of many.
1.3. Design Rationale
This section explains why certain HTML features are not part of XHTML Basic.
1.3.1. Style Sheets
The style element is not supported. External style sheets
are recommended. The link element can be used to include
external style sheets. The div and span
elements and the class attribute are supported to hook
style information onto the structure. Separation between structure and
presentation allows user agents to download the style sheets if they
support style sheets; user agents that do not support style sheets
can ignore the external stylesheet. The media attribute can be
used to select the appropriate style sheets. See the section on "Media
types" in the HTML
4.01 specification ([HTML4], section 14.2.4)
for more details.
1.3.2. Script and Events
The script and noscript elements are
not supported. Usually small devices have limited memory and
CPU power.
Execution of script programs may not be supported. Contents
should be readable even if scripts are not executed.
Event handler attributes used to invoke script programs are not supported.
Events are device dependent. An incoming-call event is unlikely to happen
in a television. A generic event handling mechanism would be more appropriate
than hardwiring the event names in the document type definition.
1.3.3. Presentation
Many simple Web clients cannot display fonts other than monospace.
Bi-directional text, bold faced font, and other text extension elements
are not supported.
It is recommended that style sheets be used to create a presentation
that is appropriate for the device.
1.3.4. Forms
Basic
XHTML
forms ([XHTMLMOD], section 5.5.1) are
supported. Since only devices with a local file system can take advantage
of file and image input types in forms, they are not included in the basic
forms. Also, content developers should keep in mind that users may not be
able to input many characters from some devices (e.g. from a mobile phone).
1.3.5. Tables
Basic
XHTML
tables ([XHTMLMOD], section 5.6.1) are
supported, but tables can be difficult to display on small devices.
It is recommended that content developers follow
the Web Content Accessibility Guidelines 1.0 for
creating accessible tables
([WCAG10], Guideline 5).
Note that in the Basic Tables Module, nesting of tables is prohibited.
1.3.6. Frames
Frames are not supported. Frames depend on a screen interface and
may not be applicable to some small appliances like phones, pagers,
and watches.
2. Conformance
This section is normative.
2.1. Document Conformance
A Conforming XHTML Basic
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:
The document must conform to the constraints expressed in
Appendix B.
The root element of the document must be <html>.
The name of the default namespace on the root element must be the
XHTML
namespace name, http://www.w3.org/1999/xhtml.
There must be a DOCTYPE declaration in the document prior to
the root element.
If present, the public identifier included in the DOCTYPE declaration must
reference the DTD found
in Appendix B using its Formal Public Identifier.
The system identifier may be modified appropriately.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
The DTD subset
must not be used to override any parameter entities in the
DTD.
2.2. User Agent Conformance
The user agent must conform to the
"User Agent Conformance"
section of the XHTML 1.0 specification
([XHTML1], section 3.2).
3.
The XHTML
Basic Document Type
This section is normative.
The XHTML
Basic document type is defined as a set of XHTML modules.
All XHTML
modules are defined in the "Modularization of XHTML"
specification [XHTMLMOD].
XHTML
Basic consists of the following XHTML modules:
NOTE:
Since the HTML
event handler attributes are not included in XHTML Basic,
form controls outside forms may not function as expected by the user.
4. How to Use XHTML Basic
Although XHTML Basic can
be used as it is - a simple XHTML language
with text, links, and images - the intention of its simple design is
for use as a host language. A host language can contain a mix of
vocabularies all rolled into one document type. It is natural that
XHTML is
the host language, since that is what most Web developers are used to.
When markup from other languages is added to XHTML Basic,
the resulting document type will be an extension of XHTML Basic.
Content developers can develop for XHTML Basic or
take advantage of the extensions. The goal of
XHTML
Basic is to serve as a common language supported by various kinds of
user agents.
5. Acknowledgements
This specification was prepared by
the W3C
HTML Working Group.
The members were:
Steven Pemberton, CWI (HTML Working Group Chair)
Robert Adams, Intel (until November 2000)
Murray Altheim, Sun Microsystems
Takuya Asada, W3C
(until October 2000)
Daniel Austin, Mozquito Technologies
Mark Baker, Sun Microsystems
Wayne Carr, Intel
Tantek Çelik, Microsoft
Andrew W. Donoho,
IBM
Herman Elenbaas, Philips Electronics
Beth Epperson, Netscape/AOL
Masayasu Ishikawa, W3C
(HTML Activity Lead)
Shin'ichi Matsui, Panasonic
Shane McCarron, Applied Testing and Technology
Ann Navarro, WebGeek, Inc.
Dave Raggett,
W3C/Openwave Systems
Sebastian Schnitzenbaumer, Mozquito Technologies
(until September 2000)
Peter Stark, Ericsson
Michel Suignard, Microsoft
Markku Vartiainen, Openwave Systems
Jeremy Wadsworth, Quark Inc.
Malte Wedel, Mozquito Technologies
Linda Welsh, Intel
Ted Wugofski, Openwave Systems
Thanks to Gary Adams (Sun Microsystems), Jonny Axelsson (Metastasis design),
Peter Chen (Philips), Dan Connolly
(W3C),
John Cowan (Reuters), Martin J. Dürst
(W3C),
Johan Hjelm (Ericsson), Ian Jacobs
(W3C),
Susan Lesch (W3C),
Louis Theran (Nokia), Quinton Zondervan (Lotus), members of
the W3C
Mobile Access Interest Group,
the W3C
Synchronized Multimedia Working Group,
the W3C
WAI
Protocols and Formats Working Group,
and the WAP Forum,
for contributing, reviewing and commenting on this document.
This section contains the SGML Open
Catalog-format definition of the XHTML
Basic FPI.
-- .......................................................................... --
-- File catalog ............................................................ --
-- XHTML Basic Catalog Data File
Revision: $Id: xhtml-basic10.cat,v 2.4 2000/12/18 21:42:58 mimasa Exp $ SMI
See "Entity Management", SGML Open Technical Resolution 9401 for detailed
information on supplying and using catalog data. This document is available
from OASIS at URL:
<http://www.oasis-open.org/html/tr9401.html>
--
-- .......................................................................... --
-- SGML declaration associated with XML .................................... --
OVERRIDE YES
SGMLDECL "xml1.dcl"
-- :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: --
-- XHTML Basic DTD modular driver file ..................................... --
PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN" "xhtml-basic10.dtd"
-- XHTML Basic framework module ............................................. --
PUBLIC "-//W3C//ENTITIES XHTML Basic 1.0 Document Model 1.0//EN" "xhtml-basic10-model-1.mod"
-- End of catalog data ..................................................... --
-- .......................................................................... --
B.2.
XHTML
Basic Driver
This section contains the driver for
the XHTML
Basic document type implementation as
an XML
DTD. It relies upon
XHTML module
implementations defined in [XHTMLMOD].
<!-- XHTML Basic 1.0 DTD ...................................................... -->
<!-- file: xhtml-basic10.dtd -->
<!-- XHTML Basic 1.0 DTD
This is XHTML Basic, a proper subset of XHTML.
The Extensible HyperText Markup Language (XHTML)
Copyright 1998-2000 World Wide Web Consortium
(Massachusetts Institute of Technology, Institut National de
Recherche en Informatique et en Automatique, Keio University).
All Rights Reserved.
Permission to use, copy, modify and distribute the XHTML Basic DTD
and its accompanying documentation for any purpose and without fee is
hereby granted in perpetuity, provided that the above copyright notice
and this paragraph appear in all copies. The copyright holders make
no representation about the suitability of the DTD for any purpose.
It is provided "as is" without expressed or implied warranty.
Editors: Murray M. Altheim <mailto:altheim@eng.sun.com>
Peter Stark <mailto:Peter.Stark@ecs.ericsson.se>
Revision: $Id: xhtml-basic10.dtd,v 2.13 2000/12/18 12:56:23 mimasa Exp $ SMI
-->
<!-- This is the driver file for version 1.0 of the XHTML Basic DTD.
This DTD is identified by the PUBLIC and SYSTEM identifiers:
PUBLIC: "-//W3C//DTD XHTML Basic 1.0//EN"
SYSTEM: "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd"
-->
<!ENTITY % XHTML.version "-//W3C//DTD XHTML Basic 1.0//EN" >
<!-- Use this URI to identify the default namespace:
"http://www.w3.org/1999/xhtml"
See the Qualified Names module for information
on the use of namespace prefixes in the DTD.
-->
<!ENTITY % NS.prefixed "IGNORE" >
<!ENTITY % XHTML.prefix "" >
<!-- Reserved for use with the XLink namespace:
-->
<!ENTITY % XLINK.xmlns "" >
<!ENTITY % XLINK.xmlns.attrib "" >
<!-- For example, if you are using XHTML Basic 1.0 directly, use
the FPI in the DOCTYPE declaration, with the xmlns attribute
on the document element to identify the default namespace:
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd" >
<html xmlns="http://www.w3.org/1999/xhtml"
xml:lang="en" >
...
</html>
-->
<!-- reserved for future use with document profiles -->
<!ENTITY % XHTML.profile "" >
<!-- Bidirectional Text features
This feature-test entity is used to declare elements
and attributes used for bidirectional text support.
-->
<!ENTITY % XHTML.bidi "IGNORE" >
<?doc type="doctype" role="title" { XHTML Basic 1.0 } ?>
<!-- :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<!ENTITY % xhtml-events.module "IGNORE" >
<!ENTITY % xhtml-bdo.module "%XHTML.bidi;" >
<!ENTITY % xhtml-model.mod
PUBLIC "-//W3C//ENTITIES XHTML Basic 1.0 Document Model 1.0//EN"
"xhtml-basic10-model-1.mod" >
<!ENTITY % xhtml-framework.mod
PUBLIC "-//W3C//ENTITIES XHTML Modular Framework 1.0//EN"
"xhtml-framework-1.mod" >
%xhtml-framework.mod;
<!ENTITY % pre.content
"( #PCDATA
| %InlStruct.class;
%InlPhras.class;
%Anchor.class;
%Inline.extra; )*"
>
<!ENTITY % xhtml-text.mod
PUBLIC "-//W3C//ELEMENTS XHTML Text 1.0//EN"
"xhtml-text-1.mod" >
%xhtml-text.mod;
<!ENTITY % xhtml-hypertext.mod
PUBLIC "-//W3C//ELEMENTS XHTML Hypertext 1.0//EN"
"xhtml-hypertext-1.mod" >
%xhtml-hypertext.mod;
<!ENTITY % xhtml-list.mod
PUBLIC "-//W3C//ELEMENTS XHTML Lists 1.0//EN"
"xhtml-list-1.mod" >
%xhtml-list.mod;
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<!-- Image Module ............................................... -->
<!ENTITY % xhtml-image.module "INCLUDE" >
<![%xhtml-image.module;[
<!ENTITY % xhtml-image.mod
PUBLIC "-//W3C//ELEMENTS XHTML Images 1.0//EN"
"xhtml-image-1.mod" >
%xhtml-image.mod;]]>
<!-- Tables Module ............................................... -->
<!ENTITY % xhtml-table.module "INCLUDE" >
<![%xhtml-table.module;[
<!ENTITY % xhtml-table.mod
PUBLIC "-//W3C//ELEMENTS XHTML Basic Tables 1.0//EN"
"xhtml-basic-table-1.mod" >
%xhtml-table.mod;]]>
<!-- Forms Module ............................................... -->
<!ENTITY % xhtml-form.module "INCLUDE" >
<![%xhtml-form.module;[
<!ENTITY % xhtml-form.mod
PUBLIC "-//W3C//ELEMENTS XHTML Basic Forms 1.0//EN"
"xhtml-basic-form-1.mod" >
%xhtml-form.mod;]]>
<!-- Link Element Module ........................................ -->
<!ENTITY % xhtml-link.module "INCLUDE" >
<![%xhtml-link.module;[
<!ENTITY % xhtml-link.mod
PUBLIC "-//W3C//ELEMENTS XHTML Link Element 1.0//EN"
"xhtml-link-1.mod" >
%xhtml-link.mod;]]>
<!-- Document Metainformation Module ............................ -->
<!ENTITY % xhtml-meta.module "INCLUDE" >
<![%xhtml-meta.module;[
<!ENTITY % xhtml-meta.mod
PUBLIC "-//W3C//ELEMENTS XHTML Metainformation 1.0//EN"
"xhtml-meta-1.mod" >
%xhtml-meta.mod;]]>
<!-- Base Element Module ........................................ -->
<!ENTITY % xhtml-base.module "INCLUDE" >
<![%xhtml-base.module;[
<!ENTITY % xhtml-base.mod
PUBLIC "-//W3C//ELEMENTS XHTML Base Element 1.0//EN"
"xhtml-base-1.mod" >
%xhtml-base.mod;]]>
<!-- Param Element Module ....................................... -->
<!ENTITY % xhtml-param.module "INCLUDE" >
<![%xhtml-param.module;[
<!ENTITY % xhtml-param.mod
PUBLIC "-//W3C//ELEMENTS XHTML Param Element 1.0//EN"
"xhtml-param-1.mod" >
%xhtml-param.mod;]]>
<!-- Embedded Object Module ..................................... -->
<!ENTITY % xhtml-object.module "INCLUDE" >
<![%xhtml-object.module;[
<!ENTITY % xhtml-object.mod
PUBLIC "-//W3C//ELEMENTS XHTML Embedded Object 1.0//EN"
"xhtml-object-1.mod" >
%xhtml-object.mod;]]>
<!ENTITY % xhtml-struct.mod
PUBLIC "-//W3C//ELEMENTS XHTML Document Structure 1.0//EN"
"xhtml-struct-1.mod" >
%xhtml-struct.mod;
<!-- end of XHTML Basic 1.0 DTD ........................................... -->
B.3.
XHTML
Basic Customizations
An XHTML
Family Document Type (such as
XHTML Basic)
must define the content model that it uses. This is done through a separate
content model module that is instantiated by the
XHTML
Modular Framework. The content model module and the
XHTML Basic
Driver (above) work together to customize the module implementations to
the document type's specific requirements. The content model module for
XHTML Basic
is defined below:
<!-- ....................................................................... -->
<!-- XHTML Basic 1.0 Document Model Module .................................... -->
<!-- file: xhtml-basic10-model-1.mod
This is XHTML Basic, a proper subset of XHTML.
Copyright 1998-2000 W3C (MIT, INRIA, Keio), All Rights Reserved.
Revision: $Id: xhtml-basic10-model-1.mod,v 2.8 2000/11/03 14:28:25 mimasa Exp $ SMI
This DTD module is identified by the PUBLIC and SYSTEM identifiers:
PUBLIC "-//W3C//ENTITIES XHTML Basic 1.0 Document Model 1.0//EN"
SYSTEM "http://www.w3.org/TR/xhtml-basic/xhtml-basic10-model-1.mod"
Revisions:
(none)
....................................................................... -->
<!-- XHTML Basic Document Model
This module describes the groupings of elements that make up
common content models for XHTML elements.
-->
<!-- Optional Elements in head .............. -->
<!ENTITY % HeadOpts.mix
"( %meta.qname; | %link.qname; | %object.qname; )*" >
<!-- Miscellaneous Elements ................. -->
<!ENTITY % Misc.class "" >
<!-- Inline Elements ........................ -->
<!ENTITY % InlStruct.class "%br.qname; | %span.qname;" >
<!ENTITY % InlPhras.class
"| %em.qname; | %strong.qname; | %dfn.qname; | %code.qname;
| %samp.qname; | %kbd.qname; | %var.qname; | %cite.qname;
| %abbr.qname; | %acronym.qname; | %q.qname;" >
<!ENTITY % InlPres.class "" >
<!ENTITY % I18n.class "" >
<!ENTITY % Anchor.class "| %a.qname;" >
<!ENTITY % InlSpecial.class "| %img.qname; | %object.qname;" >
<!ENTITY % InlForm.class
"| %input.qname; | %select.qname; | %textarea.qname;
| %label.qname;"
>
<!ENTITY % Inline.extra "" >
<!ENTITY % Inline.class
"%InlStruct.class;
%InlPhras.class;
%Anchor.class;
%InlSpecial.class;
%InlForm.class;
%Inline.extra;"
>
<!ENTITY % InlNoAnchor.class
"%InlStruct.class;
%InlPhras.class;
%InlSpecial.class;
%InlForm.class;
%Inline.extra;"
>
<!ENTITY % InlNoAnchor.mix
"%InlNoAnchor.class;
%Misc.class;"
>
<!ENTITY % Inline.mix
"%Inline.class;
%Misc.class;"
>
<!-- Block Elements ......................... -->
<!ENTITY % Heading.class
"%h1.qname; | %h2.qname; | %h3.qname;
| %h4.qname; | %h5.qname; | %h6.qname;"
>
<!ENTITY % List.class "%ul.qname; | %ol.qname; | %dl.qname;" >
<!ENTITY % Table.class "| %table.qname;" >
<!ENTITY % Form.class "| %form.qname;" >
<!ENTITY % BlkStruct.class "%p.qname; | %div.qname;" >
<!ENTITY % BlkPhras.class
"| %pre.qname; | %blockquote.qname; | %address.qname;"
>
<!ENTITY % BlkPres.class "" >
<!ENTITY % BlkSpecial.class
"%Table.class;
%Form.class;"
>
<!ENTITY % Block.extra "" >
<!ENTITY % Block.class
"%BlkStruct.class;
%BlkPhras.class;
%BlkSpecial.class;
%Block.extra;"
>
<!ENTITY % Block.mix
"%Heading.class;
| %List.class;
| %Block.class;
%Misc.class;"
>
<!-- All Content Elements ................... -->
<!-- declares all content except tables
-->
<!ENTITY % FlowNoTable.mix
"%Heading.class;
| %List.class;
| %BlkStruct.class;
%BlkPhras.class;
%Form.class;
%Block.extra;
| %Inline.class;
%Misc.class;"
>
<!ENTITY % Flow.mix
"%Heading.class;
| %List.class;
| %Block.class;
| %Inline.class;
%Misc.class;"
>
<!-- end of xhtml-basic10-model-1.mod -->