The XHTML
Basic document type is a subset of
XHTML 1.1
[XHTML11].
It includes the minimal set of modules required to be an XHTML Family
document type, and in addition it includes images, forms, and basic tables.
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.
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 is the "Last Call Working Draft" of
"XHTML Basic".
The Last Call review period ends at 2359Z on 15 March 2000.
Please send review comments before the review period ends to
www-html-editor@w3.org.
Public discussion of HTML
takes place on www-html@w3.org
(archived).
To subscribe send an email to
<www-html-request@w3.org> with the word subscribe in
the subject line.
This document has been produced as part of the
W3C
HTML Activity,
and it has been prepared by the Mobile Subgroup
of the W3C HTML Working Group
(members only)
based on input from the WAP Forum
Application's group and members of the
W3C
Mobile Access Interest Group
(members only).
This document will be used by the Mobile Subgroup of
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.
This is work in progress, and does not imply endorsement by, nor
the consensus of, either
W3C membership,
WAP Forum membership,
or members of the HTML
Working Group or the Mobile Access Interest Group.
This is a draft document and may be updated, replaced or obsoleted by
other documents at any time. It is inappropriate to cite
this document as other than "work in progress".
A list of current W3C
Recommendations and other technical documents can be found at
http://www.w3.org/TR.
HTML 4 was
designed for large devices, overlapping windows/frames menus, mouse
input pointing device, high powered
CPU, large
power supply. Requiring a full fledge 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. Transformation between
XHTML
based languages is easier if they share a common set of elements. The goal of
XHTML Basic
is to converge various
HTML subset into
one common subset of
XHTML.
The document type definition for
XHTML
Basic is implemented based on the
XHTML
modules defined in Modularized
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. The fact that most content developers are familiar with
HTML makes it
appropriate as a host language, that include markup modules from
other languages using the methods described in "Building
XHTML
Modules" [XHTMLMOD]. For example,
XHTML
Basic may be extended with an Event Module that is more generic than
the traditional HTML
4 event system.
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, fixed set of attribute event handlers,
and objects) were developed for a desktop computer type of client,
they have proved to be inappropriate for many non-desktop devices.
We believe
XHTML
Basic will be extended and built upon. Extending
XHTML
from a common and basic set of features, instead of many almost
identical subsets or the too large set of functions in
HTML 4,
we think is good for interoperability on the Web, as well as
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 that 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 stylesheets. 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 mehanism 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. However, phrasal elements such as emphasize, em, and headers are supported.
It is recommended that style sheets are used to create a presentation
that is appropriate for the device.
1.3.4. Forms
Basic
XHTML
forms ([XHTMLMOD], section 4.5.1) 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 a mobile phone).
1.3.5. Tables
Basic
XHTML
tables ([XHTMLMOD], section 4.6.1) are
supported, but tables can be difficult to display on small devices.
Content developers are recommended to follow the
accessability
guidelines for tables ([WAI-WEBCONTENT],
Guideline 5).
Note that in Basic Tables Module, nesting of tables is prohibited.
1.3.6. Frames
Frames are not supported. Frames depend on screen interface and are not
part of XHTML
1.1.
1.3.7. Objects
Images are supported using the img element.
The object and param elements are not supported.
Limited input capabilities, for example no pointing device, has
excluded image-maps.
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:
It must validate against the
DTD found 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"
"xhtml-basic10.dtd">
2.2. User Agent Conformance
The user agent must conform to the
"User Agent Conformance"
section of the
XHTML
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 with its simple design is to use it 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 the
XHTML Basic
or take advantage of the extensions. The point is that
XHTML Basic
always is the common language that user agents supports. See "Building
XHTML
Modules" [BUILDING] for information
about how to define markup language modules that are compatible with
the modularization framework used by
XHTML.
5. Acknowledgements
Thanks to Gary Adams (Sun), Johan Hjelm
(W3C/Ericsson),
Wayne Carr (Intel) and the
W3C
HTML Working Group
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 2.2 2000/02/09 21:33:57 altheim 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/cover/tr9401.html>
--
-- .......................................................................... --
-- SGML declaration associated with XHTML .................................. --
OVERRIDE YES
SGMLDECL "xml1.dcl"
-- for use with non-Unicode compatible parsers: --
-- SGMLDECL "xml1n.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.
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:stark@corp.phone.com>
Revision: $Id: xhtml-basic10.dtd,v 2.3 2000/02/10 00:12:44 altheim Exp $ SMI
-->
<!-- This is the driver file for version 1.0 of the XHTML Basic DTD.
Please use this formal public identifier to identify it:
"-//W3C//DTD XHTML Basic 1.0//EN"
-->
<!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 % XHTML.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"
"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" >
<!-- :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<!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;]]>
<!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 2.2 2000/02/10 00:12:44 altheim 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 "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 % Head-opts.mix
"( %Meta.qname; | %Link.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;" >
<!ENTITY % Inline.extra
"| %Input.qname; | %Select.qname; | %Textarea.qname;
| %Label.qname;"
>
<!ENTITY % Inline.class
"%Inlstruct.class;
%Inlphras.class;
%Anchor.class;
%Inlspecial.class;
%Inline.extra;"
>
<!ENTITY % Inline-noA.class
"%Inlstruct.class;
%Inlphras.class;
%Inlspecial.class;
%Inline.extra;"
>
<!ENTITY % Inline-noA.mix
"%Inline-noA.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 % Block.extra
"%Table.class;
%Form.class;"
>
<!ENTITY % Block.class
"%Blkstruct.class;
%Blkphras.class;
%Block.extra;"
>
<!ENTITY % Block.mix
"%Heading.class;
| %List.class;
| %Block.class;
%Misc.class;"
>
<!-- All Content Elements ................... -->
<!-- declares all content except tables
-->
<!ENTITY % Flow-noTable.mix
"%Heading.class;
| %List.class;
| %Blkstruct.class;
%Blkphras.class;
%Form.class;
| %Inline.class;
%Misc.class;"
>
<!ENTITY % Flow.mix
"%Heading.class;
| %List.class;
| %Block.class;
| %Inline.class;
%Misc.class;"
>
<!-- end of xhtml-basic10-model-1.mod -->