Detecting and Confirming browser window close/navigation events
onunload event didnt quite work in mozilla or internet explorer
another event called onbeforeunload gives a better desired effect
window.onbeforeunload = function unloadEvent()
{
return ("Are you sure you want to navigate away from the page.");
}
or still better
window.onbeforeunload = function unloadEvent()
{
return ("");
}
for just a confirmation.
This event is available on Mozilla and Internet Explorer [...]