asp.netpageloadwindow.onunload

Javascript window.onunload fires off after Page_Load


I have noticed that window.onunload event fires off AFTER page_load event which makes no sense.

This behaviour is creating an issue for me - in my unonload I clear the session, so if the Page_Load first BEFORE onunload, there are errors on the page displayed.

I would expect the javascript onunload to fire BEFORE Page_Load....is that the correct assumption?

TO CLARIFY: Let's assume I am on page test.aspx, then I click on the link that goes to the same page (say I click on a menu), what I observe is that Page_Load fires first, then onunload fires off. Makes no sense at all.


Solution

  • It's a browser-specific behaviour. Chrome and FF will send a GET requst BEFORE onunload is fired, IE8 will execute onunload first. Not sure, how the other browser handle it. Better not rely on this functionality.