Abstract
This CSS Namespaces module defines the syntax for using namespaces in CSS. It defines the @namespace rule for declaring the default namespace and binding namespaces to namespace prefixes, and it also defines a syntax that other specifications can adopt for using those prefixes in namespace-qualified names.
CSS is a language for describing the rendering of structured documents
(such as HTML and XML)
on screen, on paper, in speech, etc.
Status of this document
This section describes the status of this document at the time
of its publication. Other documents may supersede this document. A
list of current W3C publications and the latest revision of this
technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
This document was produced by the CSS Working Group as a
Recommendation.
This document has been reviewed by W3C Members, by software
developers, and by other W3C groups and interested parties, and is
endorsed by the Director as a W3C Recommendation. It is a stable
document and may be used as reference material or cited 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.
W3C encourages
everybody to implement this specification. Comments may be sent to the
(archived) public mailing list www-style@w3.org (see instructions). When sending e-mail, please put the text
“css-namespaces-3” in the subject, preferably like this:
“[css-namespaces-3] …summary of
comment…”
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the
deliverables of the group; that page also includes instructions for
disclosing a patent.
For details of the changes since the previous version, see the Changes section.
Table of Contents
1
Introduction
This section is non-normative.
This CSS Namespaces module defines syntax for using namespaces in CSS.
It defines the @namespace rule for declaring a default namespace
and for binding namespaces to namespace prefixes.
It also defines a syntax for using those prefixes to represent namespace-qualified names.
It does not define where such names are valid or what they mean:
that depends on their context and is defined by a host language,
such as Selectors ([SELECT]),
that references the syntax defined in the CSS Namespaces module.
Note that a CSS client that does not support this module will
(if it properly conforms to CSS’s forward-compatible parsing rules)
ignore all @namespace rules,
as well as all style rules that make use of namespace qualified names.
The syntax of delimiting namespace prefixes in CSS was deliberately chosen
so that these CSS clients would ignore the style rules
rather than possibly match them incorrectly.
A document or implementation cannot conform to CSS Namespaces alone,
but can claim conformance to CSS Namespaces if it satisfies the
conformance requirements in this specification when implementing CSS or
another host language that normatively references this specification.
Conformance to CSS Namespaces is defined for two classes:
- style sheet
- A CSS style
sheet (or a complete unit of another host language that normatively
references CSS Namespaces).
- interpreter
- Someone or something that interprets the semantics of a style sheet.
(CSS user
agents fall under this category.)
The conformance requirements are expressed with a combination of
descriptive assertions and RFC 2119 terminology. The key words "MUST",
"MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in the normative parts of this
document are to be interpreted as described in RFC 2119.
However, for readability, these words do not appear in all uppercase
letters in this specification. All of the text of this specification is
normative except sections explicitly marked as non-normative, examples,
and notes. [RFC2119]
Examples in this specification are introduced with the words "for example"
or are set apart from the normative text with class="example",
like this:
This is an example of an informative example.
Informative notes begin with the word "Note" and are set apart from the
normative text with class="note", like this:
Note, this is an informative note.
2.1
Terminology
Besides terms introduced by this specification,
CSS Namespaces uses the terminology defined in Namespaces in XML 1.0.