Re: §4.4 Dispatching events and "participating in a tree"

Please disregard this message.  I just received an off-list reply 
pointing out that IndexedDB propagates events on a non-DOM tree, and 
that capturing events can fire during the AT_TARGET phase. My questions 
are answered and the spec is correct as it stands

     David

On 7/4/11 2:14 PM, David Flanagan wrote:
> The "dispatch an event" algorithm branches depending on whether the 
> event target is "participating in a tree".  At first, I was thinking 
> about nodes only and assumed this test was checking whether parentNode 
> was null or not, since capturing and bubbling don't make sense for 
> nodes that have no parent.  But the definition of "participating in a 
> tree" just says that the object has a parent (even if it is null) and 
> children....
>
> Does the language really need to be this general?  Are events ever 
> dispatched on trees that are not document trees?  I don't think that 
> events ever bubble up a tree of frames, do they?
>
> So couldn't the algorithm branch based on whether target is a Node and 
> parentNode is non-null instead of the vaguer and more confusing 
> "participating in a tree" test?
>
> And here's a related question...  I've never tried registering a 
> capturing event handler on a non-Node event target like an XHR.  Such 
> an event handler could never be invoked, though.  So should the 
> addEventListener() method include the "participates in a tree" test 
> and throw an exception if the 3rd argument is true?
>
>     David

Received on Monday, 4 July 2011 21:39:19 UTC