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Resp.: capturing load events

From: Joćo Eiras <joao.eiras@gmail.com>
Date: Sun, 31 Dec 2006 19:06:18 +0000
Message-ID: <e72b1b360612311106qe5783c7ubee579b5138f8df3@mail.gmail.com>
To: Shadow2531 <shadow2531@gmail.com>
Cc: "Bjoern Hoehrmann" <derhoermi@gmx.net>, "Hallvord R. M. Steen" <hallvord@opera.com>, public-webapi@w3.org

> So, my question is, what's the reason for not wanting win t+b(2) to
fire?
The load event doesn't bubble, so it fires with the Document as
target, and doesn't go up. But compatibility with the current web
demands this.

2006/12/31, Shadow2531 <shadow2531@gmail.com>:
> On 12/29/06, Bjoern Hoehrmann <derhoermi@gmx.net> wrote:
> > * Shadow2531 wrote:
> > >[...]
> >
> > Try this fragment:
> >
> >   <pre id='r'>&#xa;</pre>
> >   <script>
> >   function trace(s)
> >     {document.getElementById('r').firstChild.nodeValue+=s+"\n";}
> >   window.addEventListener('load',function(e){
> >     trace("win cap ("+e.eventPhase+") ("+e.target+")")}, true);
> >   document.addEventListener('load',function(e){
> >     trace("doc cap ("+e.eventPhase+") ("+e.target+")")}, true);
> >   document.addEventListener('load',function(e){
> >     trace("doc t+b ("+e.eventPhase+") ("+e.target+")")}, false);
> >   window.addEventListener('load',function(e){
> >     trace("win t+b ("+e.eventPhase+") ("+e.target+")")}, false);
> >   </script>
> >   <p><img alt='' src='http://www.w3.org/Icons/valid-xhtml10' /></p>
> >
> > If you simply consider the window to be a parent of the Document, that
> > the load event does not bubble, and the load event is dispatched to the
> > img element first, then to the document, the correct result would be:
> >
> >   win cap (1) ([object HTMLImageElement])
> >   doc cap (1) ([object HTMLImageElement])
> >   win cap (1) ([object HTMLDocument])
> >   doc t+b (2) ([object HTMLDocument])
>
> O.K. Try the following in Opera if you would.
>
> <pre id='r'>&#xa;</pre>
> <script>
> function trace(s){
> document.getElementById('r').firstChild.nodeValue+=s+"\n";
> }
> /*capture window descendant load events*/
> window.addEventListener('load',function(e){
> var t=e.target;
> if (t==document.body) {
> /*In Opera, simulate document as target instead of body*/
> t=document;
> }
> trace("win cap ("+e.eventPhase+") ("+t+")");
> },true);
> /*capture document descendant load events*/
> document.addEventListener('load',function(e){
> /*In Opera, simulate document as target instead of body*/
> if (e.target!=document.body) {
> trace("doc cap ("+e.eventPhase+") ("+e.target+")");
> }
> },true);
> document.addEventListener('load',function(e){
> trace("doc t+b ("+e.eventPhase+") ("+e.target+")");
> },false);
> window.addEventListener('load',function(e){
> trace("win t+b ("+e.eventPhase+") ("+e.target+")");
> },false);
> </script>
> <p><img alt='' src='http://www.w3.org/Icons/valid-xhtml10' /></p>
>
> That should produce:
>
> win cap (1) ([object HTMLImageElement])
> doc cap (1) ([object HTMLImageElement])
> win cap (1) ([object HTMLDocument])
> doc t+b (2) ([object HTMLDocument])
> win t+b (2) ([object HTMLDocument])
>
> That's everything you expect except for the win t+b (2) at the end.
>
> So, my question is, what's the reason for not wanting win t+b(2) to
> fire? Is it because win cap (1) already fires a load for the Document
> and you don't want a second one firing?
>
> If so, then I assume if you get rid of the window capturing listener,
> then you'd want win t+b(2) to fire as usual?
>
> In other words, it sounds like you're saying,
> window.addEventListener("load", func, true) should override
> window.addEventListener("load", func, false).
>
> Thanks
>
> --
> burnout426
>
Received on Sunday, 31 December 2006 19:06:24 GMT

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