This document describes XML Schemas for XHTML 1.0.
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 a
Note
made available by the World Wide Web Consortium (W3C) for your information.
Publication of this Note by W3C indicates no endorsement by W3C or
the W3C Team, or any W3C Members.
This document provides informative XML Schemas for XHTML 1.0
[XHTML1].
These Schemas are still work in progress, and are likely to change in
future updates. This document may be updated, replaced, or obsoleted
by other documents at any time.
This document does not change the normative definition of XHTML 1.0.
Publication of this Note does not imply endorsement by the W3C, and it is
inappropriate to use this Note as reference material or to cite it as
other than "for your information".
A list of current W3C Recommendations
and other technical documents can be found at http://www.w3.org/TR.
XHTML 1.0 [XHTML1] reformulated HTML 4
[HTML4] as an XML 1.0 [XML]
application, and provided three DTDs corresponding to the ones defined
by HTML 4.
This document provides XML Schemas [XMLSchema]
corresponding to those DTDs - Strict, Transitional and Frameset,
giving users an opportunity to use XHTML 1.0 where XML Schema
processing is desired.
In most part, these XML Schemas are written to imitate the structure of
the XHTML 1.0 DTDs as much as possible. Differences are summarized in
the following section.
People who wish to extend or subset XHTML should look into
Modularization of XHTML in XML Schema
[XHTMLM12NSchema] instead.
XML Schemas for XHTML 1.1 [XHTML11] and
XHTML Basic [XHTMLBasic] will also be
provided when Modularization of XHTML in XML Schema
becomes stable.
1.2. Differences with DTD
There are many differences between DTD and XML Schema, but
major differences that affect the validation of XHTML 1.0 documents are
mentioned here.
Compared to the XHTML 1.0 DTDs, the XML Schema version provides
the following benefits:
Strong datatyping
The following data types provide better validation than DTD
at least partially:
Color
Coords
Character
Datetime
FrameTarget
LanguageCode
Length
MediaDesc
MultiLength
MultiLengths
Number
Pixels
tabindex attribute value
URI
Better expressive power for describing
content models
The content model of the following element describes the intended
constraints better than DTD:
However, in DTD the attribute value for
the accesskey attribute
(%Character;) is defined as CDATA,
which means any character data in any length, so DTD cannot
verify this error. XML Schema can flag this usage as an error.
Here's an another bogus example:
According to the spec, the tabindex
attribute value must be a number between 0 and 32767, so the above usage is
non-conforming, but again it's only defined as CDATA in DTD. Also,
the legend element should occur as
the first child of the fieldset element and
only one legend element may be used,
but DTD cannot express this constraint. XML Schema can enforce these
constraints.
Note:
Strictly speaking the legend element should
only be preceded by white space, but this constraint cannot be expressed
by XML Schema, either.
1.4. How to specify an XML Schema
Unlike DTD, which requires the use of the DOCTYPE declaration,
XML Schemas are not required to be specified in the instance itself.
However, when necessary, authors may specify an intended XML Schema
through the schemaLocation attribute
in the XML Schema instance namespace, typically added to the root element.
For example, if an author wishes to use
the XML Schema for XHTML 1.0 Strict provided
in this Note, the start tag of the html
element might designate the location of the XML Schema like this:
The namespace prefix xsi may be
changed to an arbitrary string. The attribute value of the
xsi:schemaLocation attribute
is a pair (or pairs) of URI references, one for the namespace name and
one for a hint as to the location of an XML Schema.
Note that this is only a hint, and different XML Schema processors might
use different XML Schemas identified by other means.
See "4.3.2 How schema definitions are located on the Web" of
XML Schema Part 1 [XMLSchema] for details.
1.5. Using DTD and XML Schema together
DTD validation and XML Schema validation are not mutually exclusive.
Sometimes authors might want to use some DTD features (e.g. entities) while
taking advantage of the XML Schema validation.
Authors may include the
xsi:schemaLocation attribute
as described in the previous section, however, those attributes are not
defined in the XHTML 1.0 DTDs, so if authors wish to use DTD and XML Schema
together, those attributes must be declared in the internal DTD subset
like this:
]>
...
For authors' convenience, non-normative XHTML 1.0 DTDs that support
those attributes are available at the following
URIs:
XHTML 1.0 (Second Edition) Strict in XML Schema
This is the same as HTML 4 Strict except for
changes due to the differences between XML and SGML.
Namespace = http://www.w3.org/1999/xhtml
For further information, see: http://www.w3.org/TR/xhtml1
Copyright (c) 1998-2002 W3C (MIT, INRIA, Keio),
All Rights Reserved.
The DTD version is identified by the PUBLIC and SYSTEM identifiers:
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"
$Id: xhtml1-strict.xsd,v 1.2 2002/08/28 08:05:44 mimasa Exp $
================ Character mnemonic entities =========================
XHTML entity sets are identified by the PUBLIC and SYSTEM identifiers:
PUBLIC "-//W3C//ENTITIES Latin 1 for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-lat1.ent"
PUBLIC "-//W3C//ENTITIES Special for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-special.ent"
PUBLIC "-//W3C//ENTITIES Symbols for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-symbol.ent"
================== Imported Names ====================================
media type, as per [RFC2045]
comma-separated list of media types, as per [RFC2045]
a character encoding, as per [RFC2045]
a space separated list of character encodings, as per [RFC2045]
a language code, as per [RFC3066]
a single character, as per section 2.2 of [XML]
one or more digits
tabindex attribute specifies the position of the current element
in the tabbing order for the current document. This value must be
a number between 0 and 32767. User agents should ignore leading zeros.
space-separated list of link types
single or comma-separated list of media descriptors
a Uniform Resource Identifier, see [RFC2396]
a space separated list of Uniform Resource Identifiers
date and time information. ISO date format
script expression
style sheet data
used for titles etc.
nn for pixels or nn% for percentage length
pixel, percentage, or relative
integer representing length in pixels
these are used for image maps
comma separated list of lengths
=================== Generic Attributes ===============================
core attributes common to most elements
id document-wide unique id
class space separated list of classes
style associated style info
title advisory title/amplification
internationalization attributes
lang language code (backwards compatible)
xml:lang language code (as per XML 1.0 spec)
dir direction for weak/neutral text
attributes for common UI events
onclick a pointer button was clicked
ondblclick a pointer button was double clicked
onmousedown a pointer button was pressed down
onmouseup a pointer button was released
onmousemove a pointer was moved onto the element
onmouseout a pointer was moved away from the element
onkeypress a key was pressed and released
onkeydown a key was pressed down
onkeyup a key was released
attributes for elements that can get the focus
accesskey accessibility key character
tabindex position in tabbing order
onfocus the element got the focus
onblur the element lost the focus
=================== Text Elements ====================================
these can only occur at block level
"Inline" covers inline or "text-level" elements
================== Block level elements ==============================
"Flow" mixes block and inline and is used for list items etc.
================== Content models for exclusions =====================
a elements use "Inline" excluding a
pre uses "Inline" excluding big, small, sup or sup
form uses "Block" excluding form
button uses "Flow" but excludes a, form and form controls
================ Document Structure ==================================
================ Document Head =======================================
content model is "head.misc" combined with a single
title and an optional base element in any order
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.
document base URI
generic metainformation
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")
style info, which may include CDATA sections
script statements, which may include CDATA sections
alternate content container for non script-based rendering
=================== Document Body ====================================
generic language/style container
=================== Paragraphs =======================================
=================== Headings =========================================
There are six levels of headings from h1 (the most important)
to h6 (the least important).
=================== Lists ============================================
Unordered list
Ordered (numbered) list
list item
definition lists - dt for term, dd for its definition
=================== Address ==========================================
information on author
=================== Horizontal Rule ==================================
=================== Preformatted Text ================================
content is "Inline" excluding "img|object|big|small|sub|sup"
=================== Block-like Quotes ================================
=================== Inserted/Deleted Text ============================
ins/del are allowed in block and inline content, but its
inappropriate to include block content within an ins element
occurring in inline content.
================== The Anchor Element ================================
content is "Inline" except that anchors shouldn't be nested
===================== Inline Elements ================================
generic language/style container
I18N BiDi over-ride
forced line break
emphasis
strong emphasis
definitional
program code
sample
something user would type
variable
citation
abbreviation
acronym
inlined quote
subscript
superscript
fixed pitch font
italic font
bold font
bigger font
smaller font
==================== Object ======================================
object is used to embed objects as part of HTML pages.
param elements should precede other content. Parameters
can also be expressed as attribute/value pairs on the
object element itself when brevity is desired.
param is used to supply a named property value.
In XML it would seem natural to follow RDF and support an
abbreviated syntax where the param elements are replaced
by attribute value pairs on the object start tag.
=================== Images ===========================================
To avoid accessibility problems for people who aren't
able to see the image, you should provide a text
description using the alt and longdesc attributes.
In addition, avoid the use of server-side image maps.
Note that in this DTD there is no name attribute. That
is only available in the transitional and frameset DTD.
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
================ Forms ===============================================
Each label must not contain more than ONE field
Label elements shouldn't be nested.
form control
the name attribute is required for all but submit & reset
option selector
option group
selectable choice
multi-line text field
The fieldset element is used to group form fields.
Only one legend element should occur in the content
and if present should only be preceded by whitespace.
NOTE: this content model is different from the XHTML 1.0 DTD,
closer to the intended content model in HTML4 DTD
fieldset label
Content is "Flow" excluding a, form and form controls
======================= Tables =======================================
Derived from 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 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"
horizontal alignment attributes for cell contents
char alignment char, e.g. char=':'
charoff offset for alignment char
vertical alignment attributes for cell contents
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.
colgroup groups a set of col elements. It allows you to group
several semantically related columns together.
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 span attribute causes the attributes of one
col element to apply to more than one column.
Scope is simpler than headers attribute for common tables
th is for headers, td for data and for cells acting as both
2.2. XHTML 1.0 Transitional
XHTML 1.0 (Second Edition) Transitional in XML Schema
This is the same as HTML 4 Transitional except for
changes due to the differences between XML and SGML.
Namespace = http://www.w3.org/1999/xhtml
For further information, see: http://www.w3.org/TR/xhtml1
Copyright (c) 1998-2002 W3C (MIT, INRIA, Keio),
All Rights Reserved.
The DTD version is identified by the PUBLIC and SYSTEM identifiers:
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
$Id: xhtml1-transitional.xsd,v 1.5 2002/08/28 09:53:29 mimasa Exp $
================ Character mnemonic entities =========================
XHTML entity sets are identified by the PUBLIC and SYSTEM identifiers:
PUBLIC "-//W3C//ENTITIES Latin 1 for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-lat1.ent"
PUBLIC "-//W3C//ENTITIES Special for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-special.ent"
PUBLIC "-//W3C//ENTITIES Symbols for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-symbol.ent"
================== Imported Names ====================================
media type, as per [RFC2045]
comma-separated list of media types, as per [RFC2045]
a character encoding, as per [RFC2045]
a space separated list of character encodings, as per [RFC2045]
a language code, as per [RFC3066]
a single character, as per section 2.2 of [XML]
one or more digits
tabindex attribute specifies the position of the current element
in the tabbing order for the current document. This value must be
a number between 0 and 32767. User agents should ignore leading zeros.
space-separated list of link types
single or comma-separated list of media descriptors
a Uniform Resource Identifier, see [RFC2396]
a space separated list of Uniform Resource Identifiers
date and time information. ISO date format
script expression
style sheet data
used for titles etc.
render in this frame
nn for pixels or nn% for percentage length
pixel, percentage, or relative
integer representing length in pixels
these are used for image maps
comma separated list of lengths
used for object, applet, img, input and iframe
a color using sRGB: #RRGGBB as Hex values
There are also 16 widely known color names with their sRGB values:
Black = #000000 Green = #008000
Silver = #C0C0C0 Lime = #00FF00
Gray = #808080 Olive = #808000
White = #FFFFFF Yellow = #FFFF00
Maroon = #800000 Navy = #000080
Red = #FF0000 Blue = #0000FF
Purple = #800080 Teal = #008080
Fuchsia= #FF00FF Aqua = #00FFFF
=================== Generic Attributes ===============================
core attributes common to most elements
id document-wide unique id
class space separated list of classes
style associated style info
title advisory title/amplification
internationalization attributes
lang language code (backwards compatible)
xml:lang language code (as per XML 1.0 spec)
dir direction for weak/neutral text
attributes for common UI events
onclick a pointer button was clicked
ondblclick a pointer button was double clicked
onmousedown a pointer button was pressed down
onmouseup a pointer button was released
onmousemove a pointer was moved onto the element
onmouseout a pointer was moved away from the element
onkeypress a key was pressed and released
onkeydown a key was pressed down
onkeyup a key was released
attributes for elements that can get the focus
accesskey accessibility key character
tabindex position in tabbing order
onfocus the element got the focus
onblur the element lost the focus
text alignment for p, div, h1-h6. The default is
align="left" for ltr headings, "right" for rtl
=================== Text Elements ====================================
these can only occur at block level
these can only occur at block level
"Inline" covers inline or "text-level" element
================== Block level elements ==============================
"Flow" mixes block and inline and is used for list items etc.
================== Content models for exclusions =====================
a elements use "Inline" excluding a
pre uses "Inline" excluding img, object, applet, big, small,
font, or basefont
form uses "Flow" excluding form
button uses "Flow" but excludes a, form, form controls, iframe
================ Document Structure ==================================
================ Document Head =======================================
content model is "head.misc" combined with a single
title and an optional base element in any order
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.
document base URI
generic metainformation
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")
style info, which may include CDATA sections
script statements, which may include CDATA sections
alternate content container for non script-based rendering
======================= Frames =======================================
inline subwindow
alternate content container for non frame-based rendering
=================== Document Body ====================================
generic language/style container
=================== Paragraphs =======================================
=================== Headings =========================================
There are six levels of headings from h1 (the most important)
to h6 (the least important).
=================== Lists ============================================
Unordered list bullet styles
Unordered list
Ordered list numbering style
1 arabic numbers 1, 2, 3, ...
a lower alpha a, b, c, ...
A upper alpha A, B, C, ...
i lower roman i, ii, iii, ...
I upper roman I, II, III, ...
The style is applied to the sequence number which by default
is reset to 1 for the first list item in an ordered list.
Ordered (numbered) list
single column list (DEPRECATED)
multiple column list (DEPRECATED)
LIStyle is constrained to: "(ULStyle|OLStyle)"
list item
definition lists - dt for term, dd for its definition
=================== Address ==========================================
information on author
=================== Horizontal Rule ==================================
=================== Preformatted Text ================================
content is "Inline" excluding
"img|object|applet|big|small|sub|sup|font|basefont"
=================== Block-like Quotes ================================
=================== Text alignment ===================================
center content
=================== Inserted/Deleted Text ============================
ins/del are allowed in block and inline content, but its
inappropriate to include block content within an ins element
occurring in inline content.
================== The Anchor Element ================================
content is "Inline" except that anchors shouldn't be nested
===================== Inline Elements ================================
generic language/style container
I18N BiDi over-ride
forced line break
emphasis
strong emphasis
definitional
program code
sample
something user would type
variable
citation
abbreviation
acronym
inlined quote
subscript
superscript
fixed pitch font
italic font
bold font
bigger font
smaller font
underline
strike-through
strike-through
base font size
local change to font
==================== Object ======================================
object is used to embed objects as part of HTML pages.
param elements should precede other content. Parameters
can also be expressed as attribute/value pairs on the
object element itself when brevity is desired.
param is used to supply a named property value.
In XML it would seem natural to follow RDF and support an
abbreviated syntax where the param elements are replaced
by attribute value pairs on the object start tag.
=================== Java applet ==================================
One of code or object attributes must be present.
Place param elements before other content.
=================== Images ===========================================
To avoid accessibility problems for people who aren't
able to see the image, you should provide a text
description using the alt and longdesc attributes.
In addition, avoid the use of server-side image maps.
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
================ Forms ===============================================
Each label must not contain more than ONE field
Label elements shouldn't be nested.
form control
the name attribute is required for all but submit & reset
option selector
option group
selectable choice
multi-line text field
The fieldset element is used to group form fields.
Only one legend element should occur in the content
and if present should only be preceded by whitespace.
NOTE: this content model is different from the XHTML 1.0 DTD,
closer to the intended content model in HTML4 DTD
fieldset label
Content is "Flow" excluding a, form and form controls
single-line text input control (DEPRECATED)
======================= Tables =======================================
Derived from 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 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"
horizontal placement of table relative to document
horizontal alignment attributes for cell contents
char alignment char, e.g. char=':'
charoff offset for alignment char
vertical alignment attributes for cell contents
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.
colgroup groups a set of col elements. It allows you to group
several semantically related columns together.
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 span attribute causes the attributes of one
col element to apply to more than one column.
Scope is simpler than headers attribute for common tables
th is for headers, td for data and for cells acting as both
2.3. XHTML 1.0 Frameset
XHTML 1.0 (Second Edition) Frameset in XML Schema
This is the same as HTML 4 Frameset except for
changes due to the differences between XML and SGML.
Namespace = http://www.w3.org/1999/xhtml
For further information, see: http://www.w3.org/TR/xhtml1
Copyright (c) 1998-2002 W3C (MIT, INRIA, Keio),
All Rights Reserved.
The DTD version is identified by the PUBLIC and SYSTEM identifiers:
PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd"
$Id: xhtml1-frameset.xsd,v 1.5 2002/08/28 09:53:29 mimasa Exp $
================ Character mnemonic entities =========================
XHTML entity sets are identified by the PUBLIC and SYSTEM identifiers:
PUBLIC "-//W3C//ENTITIES Latin 1 for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-lat1.ent"
PUBLIC "-//W3C//ENTITIES Special for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-special.ent"
PUBLIC "-//W3C//ENTITIES Symbols for XHTML//EN"
SYSTEM "http://www.w3.org/TR/xhtml1/DTD/xhtml-symbol.ent"
================== Imported Names ====================================
media type, as per [RFC2045]
comma-separated list of media types, as per [RFC2045]
a character encoding, as per [RFC2045]
a space separated list of character encodings, as per [RFC2045]
a language code, as per [RFC3066]
a single character, as per section 2.2 of [XML]
one or more digits
tabindex attribute specifies the position of the current element
in the tabbing order for the current document. This value must be
a number between 0 and 32767. User agents should ignore leading zeros.
space-separated list of link types
single or comma-separated list of media descriptors
a Uniform Resource Identifier, see [RFC2396]
a space separated list of Uniform Resource Identifiers
date and time information. ISO date format
script expression
style sheet data
used for titles etc.
render in this frame
nn for pixels or nn% for percentage length
pixel, percentage, or relative
comma-separated list of MultiLength
integer representing length in pixels
these are used for image maps
comma separated list of lengths
used for object, applet, img, input and iframe
a color using sRGB: #RRGGBB as Hex values
There are also 16 widely known color names with their sRGB values:
Black = #000000 Green = #008000
Silver = #C0C0C0 Lime = #00FF00
Gray = #808080 Olive = #808000
White = #FFFFFF Yellow = #FFFF00
Maroon = #800000 Navy = #000080
Red = #FF0000 Blue = #0000FF
Purple = #800080 Teal = #008080
Fuchsia= #FF00FF Aqua = #00FFFF
=================== Generic Attributes ===============================
core attributes common to most elements
id document-wide unique id
class space separated list of classes
style associated style info
title advisory title/amplification
internationalization attributes
lang language code (backwards compatible)
xml:lang language code (as per XML 1.0 spec)
dir direction for weak/neutral text
attributes for common UI events
onclick a pointer button was clicked
ondblclick a pointer button was double clicked
onmousedown a pointer button was pressed down
onmouseup a pointer button was released
onmousemove a pointer was moved onto the element
onmouseout a pointer was moved away from the element
onkeypress a key was pressed and released
onkeydown a key was pressed down
onkeyup a key was released
attributes for elements that can get the focus
accesskey accessibility key character
tabindex position in tabbing order
onfocus the element got the focus
onblur the element lost the focus
text alignment for p, div, h1-h6. The default is
align="left" for ltr headings, "right" for rtl
=================== Text Elements ====================================
these can only occur at block level
these can only occur at block level
"Inline" covers inline or "text-level" element
================== Block level elements ==============================
"Flow" mixes block and inline and is used for list items etc.
================== Content models for exclusions =====================
a elements use "Inline" excluding a
pre uses "Inline" excluding img, object, applet, big, small,
sub, sup, font, or basefont
form uses "Flow" excluding form
button uses "Flow" but excludes a, form, form controls, iframe
================ Document Structure ==================================
================ Document Head =======================================
content model is "head.misc" combined with a single
title and an optional base element in any order
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.
document base URI
generic metainformation
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")
style info, which may include CDATA sections
script statements, which may include CDATA sections
alternate content container for non script-based rendering
======================= Frames =======================================
only one noframes element permitted per document
reserved frame names start with "_" otherwise starts with letter
tiled window within frameset
inline subwindow
alternate content container for non frame-based rendering
=================== Document Body ====================================
generic language/style container
=================== Paragraphs =======================================
=================== Headings =========================================
There are six levels of headings from h1 (the most important)
to h6 (the least important).
=================== Lists ============================================
Unordered list bullet styles
Unordered list
Ordered list numbering style
1 arabic numbers 1, 2, 3, ...
a lower alpha a, b, c, ...
A upper alpha A, B, C, ...
i lower roman i, ii, iii, ...
I upper roman I, II, III, ...
The style is applied to the sequence number which by default
is reset to 1 for the first list item in an ordered list.
Ordered (numbered) list
single column list (DEPRECATED)
multiple column list (DEPRECATED)
LIStyle is constrained to: "(ULStyle|OLStyle)"
list item
definition lists - dt for term, dd for its definition
=================== Address ==========================================
information on author
=================== Horizontal Rule ==================================
=================== Preformatted Text ================================
content is "Inline" excluding
"img|object|applet|big|small|sub|sup|font|basefont"
=================== Block-like Quotes ================================
=================== Text alignment ===================================
center content
=================== Inserted/Deleted Text ============================
ins/del are allowed in block and inline content, but its
inappropriate to include block content within an ins element
occurring in inline content.
================== The Anchor Element ================================
content is "Inline" except that anchors shouldn't be nested
===================== Inline Elements ================================
generic language/style container
I18N BiDi over-ride
forced line break
emphasis
strong emphasis
definitional
program code
sample
something user would type
variable
citation
abbreviation
acronym
inlined quote
subscript
superscript
fixed pitch font
italic font
bold font
bigger font
smaller font
underline
strike-through
strike-through
base font size
local change to font
==================== Object ======================================
object is used to embed objects as part of HTML pages.
param elements should precede other content. Parameters
can also be expressed as attribute/value pairs on the
object element itself when brevity is desired.
param is used to supply a named property value.
In XML it would seem natural to follow RDF and support an
abbreviated syntax where the param elements are replaced
by attribute value pairs on the object start tag.
=================== Java applet ==================================
One of code or object attributes must be present.
Place param elements before other content.
=================== Images ===========================================
To avoid accessibility problems for people who aren't
able to see the image, you should provide a text
description using the alt and longdesc attributes.
In addition, avoid the use of server-side image maps.
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
================ Forms ===============================================
Each label must not contain more than ONE field
Label elements shouldn't be nested.
form control
the name attribute is required for all but submit & reset
option selector
option group
selectable choice
multi-line text field
The fieldset element is used to group form fields.
Only one legend element should occur in the content
and if present should only be preceded by whitespace.
NOTE: this content model is different from the XHTML 1.0 DTD,
closer to the intended content model in HTML4 DTD
fieldset label
Content is "Flow" excluding a, form and form controls
single-line text input control (DEPRECATED)
======================= Tables =======================================
Derived from 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 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"
horizontal placement of table relative to document
horizontal alignment attributes for cell contents
char alignment char, e.g. char=":"
charoff offset for alignment char
vertical alignment attributes for cell contents
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.
colgroup groups a set of col elements. It allows you to group
several semantically related columns together.
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 span attribute causes the attributes of one
col element to apply to more than one column.
Scope is simpler than headers attribute for common tables
th is for headers, td for data and for cells acting as both
References
[HTML4]
"HTML 4.01
Specification", W3C Recommendation, D. Raggett, A. Le Hors,
I. Jacobs, eds., 24 December 1999.
Available at: http://www.w3.org/TR/1999/REC-html401-19991224
The latest version is
available at: http://www.w3.org/TR/xhtml1
[XHTML11]
"XHTML™
1.1 - Module-based XHTML", W3C Recommendation,
M. Altheim, S. McCarron, eds., 31 May 2001.
Available at: http://www.w3.org/TR/2001/REC-xhtml11-20010531
The latest version
is available at: http://www.w3.org/TR/xhtml11
[XHTMLBasic]
"XHTML™ Basic", W3C Recemmendation,
M. Baker, M. Ishikawa, S. Matsui, P. Stark, T. Wugofski, T. Yamakami,
eds., 19 December 2000.
Available at: http://www.w3.org/TR/2000/REC-xhtml-basic-20001219
The latest version is
available at: http://www.w3.org/TR/xhtml-basic