[css3-mediaqueries]

http://www.w3.org/TR/2007/CR-css3-mediaqueries-20070606/#syntax
says:
  # Expressions involving unknown media features or unknown/illegal
  # values are always false.

This is changed in http://dev.w3.org/csswg/css3-mediaqueries/ to
read:
  # Unknown media features. User agents are to ignore a media query
  # when one of the specified media features is unknown.
  [...]
  # Unknown media feature values. As with unknown media features,
  # user agents are to ignore a media query when one of the
  # specified media feature values is unknown.

I'm not sure I'm happy about this change.  There's a tradeoff here:
whether to preserve that either one of "(query)" or "not (query)" is
true (the CR's way), or whether to be precise and always turn
unknown into false (the way in the dev.w3.org draft).  I can see
arguments on either side (although a supported or query-supported
keyword, prefix-able by not, could potentially get the benefits of
both sides).  (I'd hoped to write a little more about this, but
haven't had the chance.)

My bigger worry, however, is that the old wording is interoperably
implemented and tested in Acid3 (http://acid3.acidtests.org/).

-David

-- 
L. David Baron                                 http://dbaron.org/
Mozilla Corporation                       http://www.mozilla.com/

Received on Wednesday, 18 June 2008 06:24:26 UTC