W3C home > Mailing lists > Public > www-style@w3.org > July 2008

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

From: Patrick Garies <pgaries@fastmail.us>
Date: Sun, 27 Jul 2008 14:04:22 -0500
Message-ID: <488CC6B6.5080103@fastmail.us>
To: Christof Hoeke <csad7@t-online.de>
CC: www-style@w3.org

Christof Hoeke wrote:
>  ... problem is that validating real-world stylesheets might contain
>  properties which are available in most browsers (and are useful too)
>  but which are not (yet) defined in CSS 2.1. I am not quite sure if
>  that example still holds but display: inline-block is AFAIK not in
>  CSS 2.1 but very useful (I am not even talking about vendor specific
>  props like moz-opacioty etc).

|display: inline-block| has been in CSS2.1 for awhile now.

Christof Hoeke wrote:
>  IMHO a strict CSS 2.1 validator does help almost no one but the CSS
>  2.1 maintainers ;)

The W3C’s CSS validator can also do checks against CSS3 and other 
“profiles”. Flagging properties (as an error or otherwise) with a vendor 
extension is still useful when the code is peer‐reviewed, at least, with 
properties like |-moz-opacity| which are virtually obsolete (and should 
be replaced with the CSS3 |opacity| property).

As you proposed, flagging properties with a vendor extension as warnings 
(or maybe informative notices) instead of errors might be a good idea 
though. New profiles or an option could also be created (e.g., “CSS3 
with Vendor Extensions” or an “Allow Vendor Extensions” check box). None 
of this would help with properties that lack vendor extensions though.

Christof Hoeke wrote:
>  If I want to say to a customer "I use valid CSS 2.1" I am severely
>  limited, most of the times I have to use invalid CSS 2.1.

I’m a bit curious as to which properties you “severely” need (aside from 
ones that can be placed within conditional comments).

Christof Hoeke wrote:
>  I guess a similar discussion takes place with HTML/XHTML. It just is
>  not as difficult (anymore) as there are only very few elements not
>  valid (but wellformed) like e.g. <embed> (which still may be replaced
>  with valid constructs).

I know that there are well‐formedness checkers for XML (and, thus, 
XHTML) out there (e.g., see <http://www.validome.org/xml/>). I don’t 
think that I’ve ever seen an HTML 4.01 well‐formedness checker though.

Christof Hoeke wrote:
>  I won't say the validator is not useful but it would be a greater
>  help if it also could just check if my CSS is wellformed (or is this
>  actually possible?).

I looked at the W3C’s CSS validator and it doesn’t look like it. I’m not 
sure how useful it would be though since it wouldn’t test for 
unrecognized declarations. I also don’t know that things like 
Microsoft’s |filter| property or those that use their |expression()| 
value would even pass a well‐formedness check.

— Patrick Garies
Received on Sunday, 27 July 2008 19:06:21 UTC

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