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

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

From: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>
Date: Mon, 28 Jul 2008 00:38:31 +0100
Message-ID: <488D06F7.4000909@googlemail.com>
To: Christof Hoeke <csad7@t-online.de>
CC: Ingo Chao <i4chao@googlemail.com>, "www-style@w3.org" <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.

Only if they validated as something other than CSS 2.1.

I don't see how stylesheets that validate as something other than CSS 
2.1 not validating as CSS 2.1 is a problem.

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

Validity is a binary state; there is no such thing as a "strict … 

> 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. But the CSS 
> would still be "wellformed" but I cannot prove it...

CSS 2.1 doesn't have a definition of "well-formed"; the closest thing to 
that is the distinction between documents that can be parsed according 
to the CSS 2.1 grammar and documents that can't.

That's why I said "It might be useful to have a tool that could check 
documents can be parsed according to the CSS 2.1 specification." Then 
you could prove it.

You still wouldn't be able to say "I use valid CSS 2.1", because that 
wouldn't be true and I don't think validators should lie.

> 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).

Well-formedness is only defined for XML; there is no such definition for 
HTML 4.01 and no mandatory rules about how to parse HTML 4.01 when an 
error like embed is encountered, so it's not really a testable claim.

Benjamin Hawkes-Lewis
Received on Sunday, 27 July 2008 23:39:09 UTC

This archive was generated by hypermail 2.3.1 : Monday, 2 May 2016 14:27:38 UTC