[removed]: Is it possible to get any details about how the window was unloaded?

Question

I\'m developing one of those warning windows that tells the user that they may have unsaved data, but I only need it to warn them if they\'re leaving the page. Currently it

Answer 1

Short answer: There's no easy way to find out what is causing onbeforeunload to fire.

Long answer: Inside your window.onbeforeunload handler you can access the window.event object, which may have some useful properties to determine how the window is closing.

For example, if window.event.srcElement is an anchor tag, then you know that the onbeforeunload event is firing by an anchor tag being clicked.

Refer to the event and onbeforeunload pages on MSDN for more properties.

Edit: some more info I have stumbled across -

If you want to ignore ASP controls that cause post-back, you can interrogate the '__EVENTTARGET' hidden input. If this input has a non-empty string value, then the page is being posted back by an ASP control.

You could also check the keyCode property (if F5 has been pressed, causing a refresh) or the mouse position to see if the X (close) button has been clicked.