Should host objects be able to have [[Class]] "Function", "Array" etc.?

Maciej Stachowiak mjs at
Sat Nov 15 00:34:05 PST 2008

On Nov 14, 2008, at 11:38 PM, David-Sarah Hopwood wrote:

> Maciej Stachowiak wrote:
>> Specifically, we expose a "filter" property on CSSStyleDeclaration,  
>> in
>> support of the SVG filter CSS property. However, many sites test for
>> "filter" to detect support for MSIE's proprietary "filter" property,
>> which sadly has the same name but completely incompatible syntax.  
>> Thus,
>> we return this kind of magical undetectable string so if tests don't
>> detect us as IE.
> If "many" sites are relying on the proprietary IE semantics, then it's
> a bug in the CSSStyleDeclaration API that it has incompatible  
> semantics.
> Magical oddball strings won't fix this problem -- the correct long- 
> term
> fix is to rename the SVG 'filter' property so that it doesn't clash
> with something that is incompatible and already widely used.

Magic oddball strings fixed the sites that were actually broken. We  
did not do this just for fun, we ran into actual sites that had this  
problem. We don't know of sites that have a problem with the current  

I agree with you that the SVG 'filter' property should be renamed.  
This has been raised many times with the SVG Working Group and they  
did not agree. In any case I am not asking for advice on our  
compatibility strategy, just explaining it. If you'd like, I would be  
happy to raise it with the SVG WG yet again, or you are welcome to do  
so yourself.


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