How to disable beforeunload action when user is submitting a form?

Use

$('form').submit(function () {
    window.onbeforeunload = null;
});

Make sure you have this before you main submit function! (if any)

Call unbind using the beforeunload event handler:

$('form#someForm').submit(function() {
   $(window).unbind('beforeunload');
});

To prevent the form from being submitted, add the following line:

   return false;