Re: [CSS21] Are vendor-specific extensions invalid?

Ingo Chao wrote:
> Are vendor-specific extensions invalid? Or are they valid because the
>  format they should have is defined in the specification, so the 
> grammar is correct?

The CSS 2.1 specification says:

"The validity of a style sheet depends on the level of CSS used for the 
style sheet".

The specification also says:

"A valid CSS 2.1 style sheet must be written according to the grammar of 
CSS 2.1. Furthermore, it must contain only at-rules, property names, and 
property values defined in this specification. An illegal (invalid) 
at-rule, property name, or property value is one that is not valid."

http://www.w3.org/TR/CSS21/conform.html

If this statement is taken to the letter, although the specification 
describes how to parse vendor-specific properties, the property names 
and values of vendor-specific extensions are not defined in the 
specification, so they are invalid CSS 2.1.

The CSS validator correctly flags vendor-specific extensions in CSS 2.1 
stylesheets as errors.

They might conform to some other, hypothetical, CSS level, however.

--
Benjamin Hawkes-Lewis