window.onbeforeunload fires twice with IE8 under special circumstances

[christoph.strasser@…]

The event window.onbeforeunload fires twice when we click a button via Javascript.

Problem-reproduction:  http://194.48.48.79/jQueryBugs/ZZZ_jQueryOnBeforeUnloadFiresTwice_IE8.html

It happens, when clicking "click button via JavaScript" or "click dynamic generated button".

The problem occurs with IE8, it does not occure with Firefox (15) and Chrome (21).

It worked fine up to jQuery 1.6.4, since jQuery 1.7 (tested up to 1.8.1) it is broken.

[dmethvin]

I believe this is because of the use of inline handlers. Can you create a test case that does not use them for comparison? In oldIE there are situations where inline handlers are executed twice, and we're unable to fix that.

[christoph.strasser@…]

Added two additional test cases to the existing sample. It does not matter whether you use inline handlers or not. I´m able to work around the problem by clicking the other button without jquery (=only using "classic" javascript). The problem exists also with IE9. I made all my tests with Windows 7.

[christoph.strasser@…]

Made a mistake within the extended sample. My last comment was wrong, will provide an update...

[christoph.strasser@…]

After some more test cases, i think this problem is not related to jQuery.
 http://194.48.48.79/jQueryBugs/ZZZ_jQueryOnBeforeUnloadFiresTwice_IE8_withoutJQuery.html
 http://194.48.48.79/jQueryBugs/ZZZ_jQueryOnBeforeUnloadFiresTwice_IE8_withoutJQuery_withAlerts.html
 http://194.48.48.79/jQueryBugs/ZZZ_jQueryOnBeforeUnloadFiresTwice_IE8.html

At this point in time i think i was able to work around this IE-behavior successful.

[dmethvin]

If you get a chance, can you post here with a summary of the problem and your workaround? It may be useful if someone else encounters it.