How to distinguish update and close event using jQuery?

Question

Possible duplicate:
Is there a way in javascript to determine if an upload event is triggered by an update, the back button, or closing the browser?

Hello everybody

I have the following code

$(window).unload( function() { test(); }); 

test () is called when I close the window, and also if I update the window ..... How to determine if this is a refresh or close event. I need to call test() only when closing the event. Please help me...