Abstract
This specification defines in general a subset of CSS 2.1 [CSS21] that is to be considered a
baseline for interoperability between implementations of CSS on constrained devices (e.g.
mobile phones). Its intent is not to produce a profile of
CSS incompatible with
the complete specification, but rather to ensure that implementations that
due to platform limitations cannot support the entire specification
implement a common subset that is interoperable not only amongst
constrained implementations but also with complete ones. Additionally,
this specification aligns itself as much as possible with the OMA Wireless CSS 1.1 [WCSS11] specification. At the same
time, OMA is doing
alignment work in OMA
Wireless CSS 1.2 [WCSS12]. It is
aimed at aligning the mandatory compliance items between CSS Mobile Profile 2.0 and
OMA Wireless CSS 1.2 [WCSS12].
This profile is obsolete. Please see the latest CSS Snapshot for the
specifications that make up CSS.
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/.
Publication as a Working Group Note does not imply endorsement by the
W3C Membership. 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.
This document was produced by the CSS Working Group (part of
the Style Activity).
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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. An individual who has actual
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Claim(s) must disclose the information in accordance with section
6 of the W3C Patent Policy.
This document is governed by the 1 August 2014 W3C Process Document.
At this time, the CSS Working Group does not envisage
further work on this specification and does not plan to propose it as a
W3C Recommendation.
Table of Contents
1. Introduction
This document specifies a profile of CSS that is in general based on
CSS 2.1 [CSS21], but
requires as well new features from CSS 3. In addition the document
defines an OPTIONAL feature set, that is
suggested to be implemented by more advanced user agents.
The key words 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 this document are to
be interpreted as described in RFC 2119 [RFC2119].
Since the goal of this specification is to define a baseline
interoperability level, user agents MAY accept CSS documents conforming to
CSS 2.1 or subsequent
revisions of the CSS
family of Recommendations.
In order to conform to this specification, user agents, authoring
tools, and content MUST conform to the Conformance
and Error
conditions section of the CSS 2.1 specification [CSS21], with the
following modifications.
- Only features marked as supported in this specification are REQUIRED. Aside of
the REQUIRED
feature set, an additional OPTIONAL feature set is given,
that may be implemented by more advanced user agents. This feature set is
REQUIRED by
the CDF as in [WICDMobile10]. Support for a
larger set of CSS 2.1
is OPTIONAL.
- The requirement concerning which CSS 2.1 media types are
supported is tightened so that both the
handheld and
all media types MUST be accepted and processed.
Other media types MAY be accepted and processed as
well.
- The requirements that user agents MUST make it possible to select
an alternate style sheet amongst those linked from the document, as well
as provide for a way to turn off author style sheets, are relaxed to be
RECOMMENDED
behavior, but not REQUIRED.
3. Selectors
Selectors are defined in the Selectors chapter of
the CSS 2.1
specification [CSS21]. The following table
identifies which selector constructs MUST be supported amongst those
defined by CSS 2.1.
| Selector type
| Example
| Meaning
| Conformance
|
| Universal
selector
| *
| Matches any element.
| REQUIRED
|
| Type
selectors
| E
| Matches any E element.
| REQUIRED
|
| Descendant
selectors
| E F
| Matches any F element that is a descendant of an E element.
| REQUIRED
|
| Child
selectors
| E > F
| Matches any F element that is a child of an element E.
| REQUIRED
|
| The
link pseudo-classes
| E:link
| Matches element E if E is the source anchor of a hyperlink,
unvisited by a user.
| REQUIRED
|
| The
link pseudo-classes
| E:visited
| Matches element E if E is the source anchor of a hyperlink, visited
by a user.
| REQUIRED
|
| The
dynamic pseudo-classes
| E:active
| Matches element E if E is being activated by the user.
| REQUIRED
|
| The
dynamic pseudo-classes
| E:focus
| Matches element E if E has the focus (accepts keyboard events or
other forms of text input).
| REQUIRED
|
| Class
selectors
| .warning
| Language specific. (In (X)HTML, matches elements whose
class attribute contains a token with the same name.)
| REQUIRED
|
| ID
selectors
| #myid
| Matches any element with an ID equal to "myid".
| REQUIRED
|
| Grouping
| E1, E2, E3 { ... }
| Matches a group of elements, which share the same style
declarations.
| REQUIRED
|
4. At-rules
At-rules are defined in the at-rules
section of the CSS 2.1
specification [CSS21]. The following table
identifies which at-rule constructs MUST be supported amongst those
defined by CSS by
setting the at-rule as REQUIRED in the table's last
column. Only at-rules that are part of the suggested feature set for
advanced user agents are listed here as OPTIONAL.
| Rule
| Definition
| Conformance
|
| @charset
| Defines character encoding for the style sheet.
| REQUIRED
|
| @import
| Imports an external style sheet.
| REQUIRED
|
| @media
| Groups a set of style rules to apply only to one or more particular
media.
Only the handheld and all media types MUST be accepted
and processed. Other media types MAY be accepted and processed
as well.
| REQUIRED
|
| @namespace
| For declaring the default namespace and binding namespaces to
namespace prefixes.
| OPTIONAL
|
5. Properties
Properties are defined in several chapters of the CSS 2.1 specification [CSS21] and in case
of marquee properties in the CSS Marquee Module [CSS3MARQUEE]. The following
table identifies which properties MUST be supported amongst those
defined by CSS by
setting the property as REQUIRED in the table's last
column. Only properties that are part of the suggested feature set for
advanced user agents are listed here as OPTIONAL. The property syntax is
provided (expressed using the same value
specifications as CSS 2.1) when it is subsetted
from the original. Limitations that apply to a property apply equally to
its shorthand alternative.
- Content Providers will reach a larger and more
satisfied audience by following Mobile Web Best Practices [MOBILE-BP]
and CSS Techniques for
Web Content Accessibility Guidelines [WCAG10-CSS-TECHS].
- The OMA Wireless CSS 1.1 [WCSS11] introduced three extensions
'Marquee', 'Access Keys' and
'Input'. Those extensions are deprecated in OMA Wireless CSS 1.2 [WCSS12]. The 'Marquee'
functionality has been redefined by the marquee properties of the
CSS 3 box model [CSS3MARQUEE]
6. Syntax
A user agent MUST support all value types
defined in the Values section
of the CSS 2.1
specification [CSS21], with the following
exceptions:
- Support for counter values
is OPTIONAL
- Support for CSS2 System
Colors and User preferences
for fonts is OPTIONAL.
Acknowledgments
The editors wish to thank the authors of the previous version of this
document, Ted Wugofski (Openwave), Doug Dominiak (Openwave, formerly
Motorola), Peter Stark (Ericsson), and Tapas Roy (Openwave), as well as
the authors of the OMA
Wireless CSS
specifications and the CSS 2.1 specification.
Furthermore, the editors want to thank the CDF WG for their participation on this
specification.
References
Normative references
-
- [CSS21]
- Bert Bos; et al. Cascading Style
Sheets Level 2 Revision 1 (CSS 2.1) Specification. 7 June
2011. W3C Recommendation. URL: http://www.w3.org/TR/2011/REC-CSS2-20110607
- [CSS3MARQUEE]
- Bert Bos. CSS
Marquee Module Level 3. 5 December 2008. W3C Candidate
Recommendation. (Work in progress.) URL: http://www.w3.org/TR/2008/CR-css3-marquee-20081205
- [RFC2119]
- S. Bradner. Key
words for use in RFCs to Indicate Requirement Levels. RFC
2119. URL: http://www.ietf.org/rfc/rfc2119.txt
- [WICDMobile10]
- Timur Mehrvarz; et al. WICD
Mobile 1.0. 19 August 2010. W3C Working Group Note. URL: http://www.w3.org/TR/2010/NOTE-WICDMobile-20100819/
-
- [MOBILE-BP]
- Jo Rabin; Charles McCathieNevile. Mobile Web
Best Practices 1.0. 29 July 2008. W3C Recommendation. URL: http://www.w3.org/TR/2008/REC-mobile-bp-20080729/
- [WCAG10-CSS-TECHS]
- Wendy Chisholm; Gregg Vanderheiden; Ian Jacobs. CSS
Techniques for Web Content Accessibility Guidelines 1.0. 6
November 2000. W3C Note. URL: http://www.w3.org/TR/2000/NOTE-WCAG10-CSS-TECHS-20001106/
- [WCSS11]
- Open Mobile Alliance. Wireless
CSS Specification. October 2006. Approved Version 1.1. URL: http://www.openmobilealliance.org/technical/release_program/docs/Browsing/V2_3-20080331-A/OMA-WAP-WCSS-V1_1-20061020-A.pdf
- [WCSS12]
- Open Mobile Alliance. Wireless
CSS Specification Version 1.2. 21 September 2007. (Work in
progress.) URL: http://www.openmobilealliance.org/ftp/Public_documents/MCE/MAE/Permanent_documents/OMA-TS-WCSS-V1_2-20070921-D.zip