Re: scopes, execution contexts, and scripts

Boris Zbarsky wrote:
> On 1/26/10 12:58 PM, John J. Barton wrote:
>> In my unload handler for the outer DOM window I get called with window
>> location = about:blank
> 
> OK, so about:blank is being unloaded (and possibly something else is 
> being laoded instead).

and how to distinguish the (and possibly..) case from 
unload-because-we-are-being-deleted.

> 
>> // domWindow.location is about blank here...
>> setTimeout(function delayCleanup() // to allow the unload handlers to
>> complete
> 
> So you run this code off a delay...
> 
>> // domWindow.location is chrome://test/content/testDialog.xul
> 
> Which presumably got loaded instead of the about:blank.
> 
>> So somehow about:blank is getting an unload message but the domWindow
>> object I obtained from the unload handler event.target.defaultView; is
>> morphing into the window that supports my dialog.
> 
> Again, a window can have the URI loaded in it change.  This happens all 
> the time, in fact: if nothing else people browse the web.  When you 
> navigate from page A to page B the Window object involved (the one you 
> can get your hands on from script) does NOT change.  Its location.href 
> does, of course.

And so to handle this case, I guess I need to track onLocationChange 
events for every nsIDOMWindow?  I don't understand how to tell if a 
window is being destroyed after unload vs being reused.

> 
> -Boris