On Mar 11, 2011, at 7:50 PM, joe t. wrote:
Here's a sample from code that i wrote and seems to work ok (at least,
last i tested it, i no longer work there), adapted for generics:
So here's what i learned, now that my curiosity got roused...
The beforeunload event will automatically generate the prompt. If you
want to inject a custom message into that prompt (not speaking for
FF4, as i haven't tested on that with my prior code), you assign that
STRING to the event.returnValue property.
i'm pretty sure that by assigning a value to event.returnValue, the
prompt is fired. If it has no value by the time the handler returns,
the prompt does not occur.
The user is prompted with the built-in prompt, plus your custom
The event will automatically cancel ITSELF if the user hits the Cancel
button of the confirmation message.
There's no need to put a confirm in the event handler yourself. That's
what would cause the double-prompt, and the confirm you generate is
ignored by the event anyway.
That's the best i can recall, anyway. i hope it helps.
This works really nicely in Firefox 3.latest, and does what you say --
intermingles the custom message with the browser default message. But
in Safari 5.latest, closing the window does nothing -- no alert of any
kind is issued. That's why I ended up putting the confirm() in there
in the first place -- to get Safari to do something in this event.
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