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Re: [css3-mediaqueries] no list of allowed media types

From: fantasai <fantasai.lists@inkedblade.net>
Date: Thu, 03 Apr 2008 00:36:16 -0700
Message-ID: <47F488F0.4020706@inkedblade.net>
To: www-style@w3.org

L. David Baron wrote:
> On Wednesday 2008-04-02 20:31 -0700, L. David Baron wrote:
>> http://dev.w3.org/csswg/css3-mediaqueries/#syntax says:
>>
>> # Media queries involving unknown media types are ignored. 
>>
>> This is different from the most recent CR,
>> http://www.w3.org/TR/2007/CR-css3-mediaqueries-20070606/#syntax ,
>> which says:
>>
>> ...
> To follow up on this one as well -- here I also prefer the text in
> the CR over the text in the editor's draft, although my feelings are
> not as strong as in the other case.  I think giving authors the
> ability to do if/else with a guarantee that at exactly one of the
> options will be applied is probably more valuable than giving
> authors the ability to detect whether the media feature is correctly
> detected.  (It would be better to be able to do both, but I don't
> see a trivial way to do that.)  That said, I could be convinced
> otherwise.
> 
> I wrote a testcase to try to test this:
>   http://dbaron.org/css/test/2008/mq-unknown-type
> The only browsers I've found that support not (Opera 9.5 beta 1 and
> Safari 3.1) make it yellow, which agrees with the CR, not the
> editor's draft.

I've thought about this, and I think you're right, they should be
treated as false: since media types are defined to be mutually
exclusive, a UA can only claim to match one media type (presumably
a known one).

However unknown media features and/or values should still cause the
media query to be ignored as agreed in
   http://www.w3.org/blog/CSS/2007/11/14/resolutions_3
because the UA can't know whether the feature applies to it or not.
Speaking of which,
   # Expressions involving unknown media features or unknown/illegal
   # values are ignored.
should be s/Expressions/Media queries/: we want to drop the media
query, not just the unknown expression.

~fantasai
Received on Thursday, 3 April 2008 07:37:38 GMT

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