[whatwg] Specification unclear about how HTMLElement.prototype.onscroll's getter/setter should behave for "body" elements

[Cameron McCormack]

On 4/12/12 6:31 AM, Boris Zbarsky wrote:
> It's a similar situation, yes.  But in this case I don't see why you'd
> need an IDL annotation of any sort at all.  If you want the behavior to
> be the same, just don't define onscroll on Bar at all and define the one
> on Foo to special case the two Foo subclasses you care about here.  If
> you don't want it to be the same, the IDL annotation doesn't help you.

I agree.  But if you we really do need a separate namedItem (for bug 
17201) on HTMLPropertiesCollection, then there is no harm in having it 
too, but I would have it not work on other HTMLCollection objects.

So I think my suggested solution for that bug is:

   * Have the definition of HTMLCollection.namedItem include a hook that
     other specifications can override for descendant classes like
     HTMLPropertiesCollection.

   * Do that overriding for HTMLPropertiesCollection.

   * Not define a distinct namedItem on HTMLPropertiesCollection.

I can see that if you did still include a namedItem on 
HTMLPropertiesCollection with its special behaviour, then you could save 
yourself effort by putting an extended attribute on HTMLCollection's one 
(which means "delegate to the subclass") but I don't think it's really 
necessary.

(I will put the above in the bug.)