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[whatwg] HTMLElement.onload

From: Simon Pieters <simonp@opera.com>
Date: Sun, 25 Oct 2009 22:14:12 +0200
Message-ID: <op.u2djxyrbidj3kv@simon-pieterss-macbook.local>
On Fri, 23 Oct 2009 17:16:13 +0300, Markus Ernst <derernst at gmx.ch> wrote:

> In 6.5.6.2 of the spec I found, that the onload event handler is now  
> available for every HTML element in HTML5, which I think is a great  
> improvement. But there is something on the load event, that I think  
> would be worth some words to clarify.
>
> According to 6.11.2 the load event is fired when the whole document is  
> loaded; I did not find anything about element-specific load events. So I  
> assume that element1.onload is triggered by the same event as  
> element2.onload - the following two bodies would be equivalent:
>
> <body>
>    <p onload="dosomething(this)">Text</p>
>    <p onload="dosomethingelse(this)">Text</p>
> </body>
>
> <body onload="dosomething(document.getElementById('foo'));
>    dosomethingelse(document.getElementById('bar'))">
>    <p id="foo">Text</p>
>    <p id="bar">Text</p>
> </body>
>
> Is this assumption correct?

No. The first registers two listeners on two elements, and the second  
registers one listener on the window. When the document loads, a load  
event is fired on the window, but there's nothing that fires load events  
on <p>, so for the first example to do anything you have to fire the event  
yourself with script.


> Generally, the list of events that must be supported by all HTML  
> elements looks somehow confusing to me, as there are some events that  
> only apply to special types of elements, such as media players or forms  
> resp. form elements. How are e.g. onpause or oninput supposed to work if  
> applied to span or p elements?

Same as onload -- it just registers a listener. pause and input events  
don't bubble and don't fire on span or p unless you do it yourself with  
script. Maybe it doesn't make any sense to have <p onpause>, but it's  
easier to implement (which in turn means less bugs and thus less headaches  
for authors) to support all event handlers everywhere.

http://www.whatwg.org/specs/web-apps/current-work/multipage/section-index.html#events-0  
(and the tables referenced from there) is useful for finding out which  
events are fired where.

HTH,
-- 
Simon Pieters
Opera Software
Received on Sunday, 25 October 2009 13:14:12 UTC

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