backbone single page application alert user when URL changes

Question

I am working on a single page application at the moment, and I wanting to show some UI is a user, refreshes the page, closes the tab, or navigates away, the reason for this is doing any of these will cancel any active uploads, and I want the user to know that.

So far I have,

$(window).on('beforeunload', function() {
   alert("!!!");
   return null;
});

This only seems to fire when I refresh the page, though. Is there away to hook this in to my router? I have a global var called App.Uploading, if that is true, I want to fire a method every time a route is accessed is that possible?

Answer 1

There is a JQuery unload function you can use:

$( window ).unload(function() {
    console.log('preventing unload!');
    return false;
});

document.location = 'http://www.google.com';