CSS Foo Module Level N

Abstract

This module introduces the foo property and related values, which do bar and baz. 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

Table of contents

1 Introduction

This section is not normative.

Provide background, motivation, etc.

2 Sample section

Look at the mark-up in this section for examples. See the documentation for more precise instructions. The companion of this template shows the processed result.

To refer to HTML, use [HTML40] (note the double square brackets). To make a normative reference, insert a “!”, like this: [CSS3SYN] The currently available list of bibliographic data can of course be extended.

We write about a property such as foo like this and about a piece of CSS code like this: foo: bar. (Note that if it looks like a "property: value", it’ll automatically link to the property.) Inline HTML and XML are similar, but use the CODE element: <blockquote>...</blockquote> and <r:xyz>...</r:xyz>.

Note: Note that the property will automatically be linked to its definition.

To define terms into the index, there are many variants, but hopefully the simplest will be the most common.

Note: Note that you can add non-normative notes like this.

Of course, multi-paragraph notes are also possible: just enclose them in a div:

Displayed examples come in eight different types: CSS examples that need no separate paragraph of explanation are put in a simple PRE:

  EM { font-style: italic }

CSS examples that need extra text need a DIV.

EM { font-style: italic }

Illegal CSS examples (examples of errors) are the same, but with class "illegal example". Examples of HTML and XML code have class "html" and "xml"respectively, but are otherwise ditto.

A formal definition of a property looks like this:

2.1 Internal display model: the display-inside property

value-name

Define values using a dl. Note that the dl wrapper specifies the default dfn type and what property it’s for, so you don’t have to repeat that information in each individual definition.

Cross-references are created by enclosing a term or phrase in <dfn> (like the word cross-references earlier in this sentence). Then an <a> without an href='' attribute with the same text content will automatically be linked. Both <dfn>s and <a>s are typed, which allows the same text to appear as different types of terms without a collision. The type can often be inferred, but sometimes it needs to be specified, like when you’re linking to a Foo WebIDL interface.

And a figure with a caption is done like this:

Don’t forget to write the alt.

An open issue or editorial remark is OK in a WD, but they should be resolved/removed before the document goes to “CR” (Candidate Recommendation). Use class=“issue”.

Inline issues will be copied into an Issues Index at the end of the document, for easy reference.

/* Write WebIDL in a <pre class="idl"> as plain text. */
  interface Foo {
    readonly attribute DOMString bar;
    boolean baz(FooDict Arg1, (DOMString or Foo) Arg2);
  };

  dictionary FooDict {
    sequence<Foo> foo;
    boolean bar;
    DOMString baz = "qux";
  };

Conformance

Document conventions

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:

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.

Conformance classes

Conformance to this specification is defined for three conformance classes:

style sheet

A CSS style sheet.

renderer

A UA that interprets the semantics of a style sheet and renders documents that use them.

authoring tool

A UA that writes a style sheet.

A style sheet is conformant to this specification if all of its statements that use syntax defined in this module are valid according to the generic CSS grammar and the individual grammars of each feature defined in this module.

A renderer is conformant to this specification if, in addition to interpreting the style sheet as defined by the appropriate specifications, it supports all the features defined by this specification by parsing them correctly and rendering the document accordingly. However, the inability of a UA to correctly render a document due to limitations of the device does not make the UA non-conformant. (For example, a UA is not required to render color on a monochrome monitor.)

An authoring tool is conformant to this specification if it writes style sheets that are syntactically correct according to the generic CSS grammar and the individual grammars of each feature in this module, and meet all other conformance requirements of style sheets as described in this module.

Partial implementations

So that authors can exploit the forward-compatible parsing rules to assign fallback values, CSS renderers must treat as invalid (and ignore as appropriate) any at-rules, properties, property values, keywords, and other syntactic constructs for which they have no usable level of support. In particular, user agents must not selectively ignore unsupported component values and honor supported values in a single multi-value property declaration: if any value is considered invalid (as unsupported values must be), CSS requires that the entire declaration be ignored.

Experimental implementations

To avoid clashes with future CSS features, the CSS2.1 specification reserves a prefixed syntax for proprietary and experimental extensions to CSS.

Prior to a specification reaching the Candidate Recommendation stage in the W3C process, all implementations of a CSS feature are considered experimental. The CSS Working Group recommends that implementations use a vendor-prefixed syntax for such features, including those in W3C Working Drafts. This avoids incompatibilities with future changes in the draft.

Non-experimental implementations

Once a specification reaches the Candidate Recommendation stage, non-experimental implementations are possible, and implementors should release an unprefixed implementation of any CR-level feature they can demonstrate to be correctly implemented according to spec.

To establish and maintain the interoperability of CSS across implementations, the CSS Working Group requests that non-experimental CSS renderers submit an implementation report (and, if necessary, the testcases used for that implementation report) to the W3C before releasing an unprefixed implementation of any CSS features. Testcases submitted to W3C are subject to review and correction by the CSS Working Group.

Further information on submitting testcases and implementation reports can be found from on the CSS Working Group’s website at http://www.w3.org/Style/CSS/Test/. Questions should be directed to the public-css-testsuite@w3.org mailing list.

References

Normative References

Informative References

Index

Property index

Issues Index