[selectors-api] Comment on Interoperability Considerations

Dear Web Apps WG,

I've reviewed the Selectors API [1], and have one comment:

The Interoperability Considerations section states that in certain  
cases "such implementations could return different results from those  
that do support them". While this is a non-normative section, just  
referring to "different results" seems a bit too vague and is not  
really helpful for applications relying on the specification. Even  
more worrying, after reading the rest of the specification and the  
underlying Selectors specification [2] I can still not tell what the  
intended behavior is. The Selectors specification introduces Profiles,  
which indicate which selectors are supported ("accepted") by a  
specification using Selectors, but it neither introduces a similar  
concept for implementations, nor does it seem to specify the behavior  
resulting from the use of selectors that are not supported by a  
specification or an implementation.

I would expect the specification to prescribe
- either that the implementation raises an exception when given a  
selector that it doesn't support,
- or that the implementation return null (for querySelector) or an  
empty list (for querySelectorAll) when given a selector that it  
doesn't support.

Best regards,
Norbert Lindenberg

[1] http://www.w3.org/TR/2008/WD-selectors-api-20081114/

[2] http://www.w3.org/TR/2005/WD-css3-selectors-20051215/

Received on Sunday, 14 December 2008 09:01:19 UTC