Is calling an ajax function possible before someone's decide to leave the page. I mean i can ask the user if user wants to leave or stay. But i dont know how to alter behaviour when user click "yes leave the page" button.
I have this code working..
<head> <script type="text/javascript"> function catchExit() { return "All your data is going to be lost. Are you sure??"; } </script> </head> <body onbeforeunload="return catchExit()"> <p> Dont leave the page. </p> </body> Here's an alternative way using confirm:
function catchExit(){ var exit = confirm("Are you sure?"); if (exit){ } } But keep in mind that AJAX can't stop the thread. That means that there's no guarantee the call:
The window will have shown the prompt and/or exited before the AJAX may have even completed. To illustrate it better:
function catchExit(){ $.ajax({ success: function(){ // this is an entirely new thread and returning a result // has ZERO effect on the original catchExit function // (And chances are it's already executed and is long gone) } }); // this (99.99% of the time) will be called long before // 'success' above is called, therefore making 'success' and its // outcome moot. return "There are unsaved changes, are you sure you want to exit?"; } 
Actually, i found a way to get my $.ajax() call worked. Setting async parameter to false works in firefox, chrome, iexplorer and safari. It only doesn't work in opera.
confirmbefore it defaults to browser behavior though.