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Re: [css-cascade] Allowing @import to be conditional on @supports queries

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 15 Jan 2015 17:02:14 -0800
Message-ID: <CAAWBYDC94sGZ2GCXqEpBh+NxX8KSbx_wdtsXbZ=5MhHppdMhHw@mail.gmail.com>
To: "L. David Baron" <dbaron@dbaron.org>
Cc: www-style list <www-style@w3.org>
On Thu, Jan 15, 2015 at 4:47 PM, L. David Baron <dbaron@dbaron.org> wrote:
> On Thursday 2015-01-15 16:35 -0800, Tab Atkins Jr. wrote:
>> I propose that we allow this by adding a
>> "supports(<supports-condition>)" function to the end @import grammar,
>> like:
>>
>> ```
>> @import [ <url> | <string> ] [ <media-query-list> ||
>> supports(<supports-condition>) ]? ;
>> ```
>>
>> In other words, you can supply a media condition and/or a supports
>> condition.  If we add more conditional rules, we can add more to this
>> clause as well.
>
> Sounds good.
>
> Previously discussed in
> https://lists.w3.org/Archives/Public/www-style/2011Jun/0329.html
> and deferred to level 4 in:
> https://lists.w3.org/Archives/Public/www-style/2012Oct/0275.html

That was before Cascade took over defining @import from 2.1.  We could
probably just bake it into Cascade today.

> Presumably we'd want to have a requirement that UAs actually *not*
> load the sheets through such a supports-query when it fails to
> match?  (Also, CSSImportRule.styleSheet MUST be null, even if the
> sheet is loaded through some other link.)

Yes, I think that's pretty important.

~TJ
Received on Friday, 16 January 2015 01:03:01 UTC

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