How to stop window unloading?

Question

when user click a another link or refresh the page, the window will unload, how to prevent/confirm it?

Answer 1

From here http://bytes.com/topic/javascript/insights/825556-using-onbeforeunload-javascript-event

<script type="text/javascript">
     window.onbeforeunload = function(){ return 'Your Returned String Goes Here';}
</script>