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Re: capturing load events

From: Joćo Eiras <joao.eiras@gmail.com>
Date: Thu, 28 Dec 2006 00:12:31 -0000
To: "Hallvord R. M. Steen" <hallvord@opera.com>
Cc: "www-dom@w3.org" <www-dom@w3.org>
Message-ID: <op.tk8ti5btjz3wb9@dragast>

I too have 3 questions:

   - is the window considered as a target in the entire event capturing and  
bubbling phases ?
     * in Gecko yes, in Opera no.

   - should events registered to the window have the document as target ?
     * both in Gecko and Opera yes.

   - should capturing of load events be supported too when registering a  
capturing event listener in the window ?
     * in Opera yes, in Gecko no as consequence of their 'fix'

The ecmascript binding needs clarification in this regard.

Hallvord R. M. Steen <hallvord@opera.com> escreveu:

> Hi,
> I have a request for clarification regarding the behaviour of capturing  
> events.
> Opera has implemented capture of load events in the document, meaning  
> that an event listener added with
> window.addEventListener('load', func, true);
> would run for every load event on IMG, SCRIPT, LINK rel="stylesheet"  
> etc. in the document.
> This is also implemented in Safari but not supported in Mozilla until  
> recently (see bug 331306 - [1])
> While we think Opera's/Safari's implementation is correct according to  
> the spec, a number of sites out there rely on Mozilla's bug and expect  
> such an event listener to run only once.
> Mozilla developers have proposed a solution in bug 335251 [2]. They  
> suggest that load events should not propagate to the "window" object in  
> the browser's JavaScript environment.
> Pros of Mozilla's suggestion:
>   - it's backwards compatible with existing content
> Cons:
> - we introduce an inconsistency to the whole event listener model that  
> means for example these two will mean very different things..
> window.addEventListener('click', func, true); // runs for any click event
> window.addEventListener('load', func, true); // runs once only
> It is not clear from the DOM Events spec how the "window" object fits  
> into the capturing/bubbling. Could this be clarified? Which behaviour  
> should be considered correct per the spec?
> [1] https://bugzilla.mozilla.org/show_bug.cgi?id=331306
> [2] https://bugzilla.mozilla.org/show_bug.cgi?id=335251
> Commentary:
> http://my.opera.com/hallvors/blog/2006/12/23/firechicken
Received on Thursday, 28 December 2006 00:12:32 GMT

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