W3C home > Mailing lists > Public > www-svg@w3.org > January 2005

Re: DOM Level 3 events

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Tue, 18 Jan 2005 18:56:44 -0600
Message-ID: <41EDB04C.5090606@mit.edu>
To: Peter Sorotokin <psorotok@adobe.com>
CC: Jon Ferraiolo <jon.ferraiolo@adobe.com>, Cameron McCormack <cam-www-svg@aka.mcc.id.au>, www-svg@w3.org

Peter Sorotokin wrote:

>>>> 2)  That the implementation is keeping the event listeners for the 
>>>> two types in
>>>>     separate lists (is this desirable?  Should registering a 
>>>> listener for both
>>>>     types involved make it get the event twice?).
>>> You can do it per-listener rather than on per-list basis; but I'd 
>>> keep two separate lists.
>> In other words, a listener registered for both event names would 
>> indeed get the event twice?
> No, in this case each event listener entry in the list would have to 
> store an event type for which it was registered (also would be needed 
> for unregistering).

I'm sorry, but I think you lost me.  Say I have an event listener named 
"listener" and an event target named "target".  We have our two event types 
"type1" and "type2".  I execute the following code:

   target.addEventListener("type1", listener, false);
   target.addEventListener("type2", listener, false);

when the event fires, how many times will my listener's handleEvent method be 
called?  Please note the provisions on addEventListener for registering 
identical listeners.

Further, what is the behavior of:

   target.addEventListener("type1", listener, false);
   target.removeEventListener("type2", listener, false);


The answers to these questions should be clearly documented in the specification 
of what it means for the two event names to be "equivalent".

Received on Wednesday, 19 January 2005 00:59:05 UTC

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