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

From: David Flanagan <dflanagan@mozilla.com>
Date: Mon, 04 Jul 2011 14:49:23 -0700
Message-ID: <4E123563.50209@mozilla.com>
To: www-dom@w3.org
I'm having trouble reading and writing email today :-)  I mistakenly 
replied to Olli off-list, but as everyone can see, he replied to my 
original message on-list.  So just disregard it all.  Sorry!

On 7/4/11 2:38 PM, David Flanagan wrote:
> 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 21:49:52 UTC

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