Simon Pieters schrieb:
On Fri, 23 Oct 2009 17:16:13 +0300, Markus Ernst <derer...@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.
Thank you for making this clear.
The spec says in 3.2.3: "The following event handler content attributes
may be specified on any HTML element" - with my quite trivial
understanding, I would actually expect something to happen if I do this.
The note "The attributes marked with an asterisk have a different
meaning when specified on body elements as those elements expose event
handlers of the Window object with the same names" does not correct this
expectation, but rather implies, that onload on any element has an
effect, as it is supposed to have another effect than when specified in
the body element.
I understand that the spec is not a reference manual for authors, but as
authors are actually encouraged to read the spec, I suggest to add
another note to 3.2.3, saying something like: "Note: specifying an event
handler content attribute on an element may have no effect, if the
corresponding event is not fired at this element. If you are not sure
which events are fired at which elements, refer to
http://www.whatwg.org/specs/web-apps/current-work/multipage/section-index.html#events-0.";
Also, in this events table, the description of the load event is very
rudimentary: "Fired when a resource has finished loading". I suggest
changing this to something like: "Fired at the Window object when the
document has finished loading, or at an element containing a resource,
when the resource has finished loading".
