AJAX on unload?

[Shawazi]

I have an item in my database that can be edited by multiple people. I want to have it so when a user edits the item, it locks others from editing it. I unlock it when they do other things on the page. This is all taken care of.

The problem is, if a user closes the window there is no AJAX call thrown off to unlock the item. Is there a way to add a 200MS delay before a window closes? I know I can put up an alert box to stop a user from really leaving, but I'd rather NOT have that in there saying "Are you done editing", for example

[Shawazi]

Resolution for all your leaving and refreshing needs:

window.onbeforeunload = foo;
window.onunload = foo; 
function foo() {
    //ajax as long as there is no return
}
function