[cssom][css4-mediaqueries] serializing unknown media type

On Tue, 22 May 2012 23:36:41 +0200, Kang-Hao (Kenny) Lu  
<kennyluck@csail.mit.edu> wrote:

> I noticed that IE9 is a bit different from other browsers in that it
> serializes an arbitrary media type as "unknown" instead of the original
> input.
>
> This turns out, as far as I can tell, not to create a non-conforming
> case as css3-mediaqueries doesn't say very clearly that a UA has to
> store the unknown media types. Some options:
>
> A. Don't change the spec and keep it as it is.
>
> B. Explicitly ask UA to store an unknown media type. Concrete proposal:
>
> In 3.1. Error Handling,
>
> change
>
>   # Unknown media types. Unknown media types evaluate to false.
>   # Effectively, they are treated identically to known media types that
>   # do not match the media type of the device.
>
> to (be more clarified)
>
>   | Unknown media types. Unknown media types evaluate to false.
>   | Effectively, they are treated identically to known media types that
>   | do not match the media type of the device, which means that a UA
>   | must store an unknown media type so that it is accessible via
>   | CSSOM.
>
> C. Make it undefined.
>
> (I think an explicit undefined is usually better than saying nothing at
> all.)
>
> Just in case we want a "mixed approach", these are all the media types
> IE9 recognizes: ‘aural’, ‘braille’, ‘handheld’, ‘print’, ‘projection’,
> ‘screen’, ‘tty’, ‘tv’ and ‘embossed’. Or in other words, all the media
> types listed in css3-mediaqueries besides 'speech'.

I think the IE behavior is a bug, given what the spec already says.
Replacing 'foobar' with 'unknown' isn't treating 'foobar' the same as
a known media type that doesn't match.

Ultimately though, the OM for Media Queries is defined in the CSSOM
spec, not in the Media Queries spec, so if there is anything to fix,
I suggest addressing it there. On the other hand, we might want to
pull the OM into the Media Queries 4 spec instead.

  - Florian

Received on Friday, 25 May 2012 10:24:52 UTC