There seems to be general agreement (amongst browsers, not yet the spec)
that if a document does something that causes a new load event from
within an onload handler (document.open/document.close_ the second load
event is not dispatched. This also applies to the load event on iframe
elements if an event handler in the iframe would synchronously cause a
second load event to fire.
There is not agreement about what happens where there are multiple
frames e.g. if a load event handler on iframe element A would cause a
load event in iframe B, should the handler on B fire. Gecko says yes,
WebKit no. There is a slightly rubbish demo at [1].
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).
[1] http://software.hixie.ch/utilities/js/live-dom-viewer/saved/1686
