Question

a flash movie where users can draw is calling a JS Function. Whenever something is changed in the movie calls listenToUnload(true). Whenever the save button in the Flashmovie is pressed listenToUnload(false); is called.

function listenToUnload(saved) {

   if (saved) {

      $(window).bind('unload', function() {
          closeWindowWarning;
      });

   } else if (!saved) {
       $(window).unbind('unload');
   }

}

function closeWindowWarning() { return "You haven't saved your last changes"; }

So, I actually wonder if this is the correct way to do this?
Because listenToUnload(true) could be called multiple times in a row and I don’t want to have the unload function bound multiple times to the window.

Is this the correct way of doing this? Any other approaches?

thank you

Answer 1

First, you need to bind on beforeunload, not unload.

You can store the flag (whether to confirm before unload) in a variable, or in $(document).data('confirm_unload', TRUE_OR_FALSE) and then:

function closeWindowWarning() { 
    if ($(document).data('confirm_unload'))
        return "You haven't saved your last changes"; 
}

And of course bind the beforeunload event once:

$(window).bind('beforeunload', closeWindowWarning)

You don’t need to wrap closeWindowWarning in another function.