[whatwg] Load events fired during onload handlers

Boris Zbarsky bzbarsky at MIT.EDU
Mon Jul 30 08:44:14 PDT 2012

On 7/30/12 11:10 AM, James Graham wrote:
> I don't think I have a strong opinion about what should happen here, but
> the Gecko behaviour could be easier to implement, and the WebKit
> behaviour slightly safer (presumably the point of this anomaly is to
> prevent infinite loops in load event handers).

In Gecko's case, the only thing like that I know of is that onload fires 
synchronously in Gecko in some cases, I believe. So we had to put in 
some sort of recursion guard to prevent firing onload on a parent in the 
middle of a child firing onload or something like that.  See 
<https://bugzilla.mozilla.org/show_bug.cgi?id=330089>.  Per spec, onload 
is always async, so this wouldn't be a concern.

I'm not quite sure what causes the behavior you're seeing in Gecko at 
<http://software.hixie.ch/utilities/js/live-dom-viewer/?saved=1686>, but 
at first glance it's sort of accidental...  Which doesn't mean we 
shouldn't spec it, of course; it just means that figuring out what to 
spec is harder.  :(

If desired, I can try to figure out exactly why there's only one load 
event on the first iframe there.  Let me know.


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