Unbind window.onbeforeunload() cancel

Question

i'm binding a function to an event with

window.onbeforeunload = function() {
 somefunction()
}

which is working on unload as planned, but if they cancel the onbeforeunload the function is still attached, is it possible to check if the user cancels onbeforeunload

Answer 1

Actually, I found it was quite easy: I just set

window.onbeforeunload = null;

for each click before it was run, allowing the event handler to be run afterwards.

Answer 2

or you can just return null

window.onbeforeunload = function() {
  return null;
};

I am using following snippet for that: window.onbeforeunload gist