onUnload method on plugin Wordpress

Question

I'm creating a plugin for WordPress. But I can't enter the method onUnload.

I tried to include it in the body tag, but doesn't work.

Is there a way to use this method?

Answer 1

try this:

window.onbeforeunload = nameFunction;

Answer 2

Solution by OP.

<script type=”text/javascript”>

window.onbeforeunload = askUser;

function askUser(){
  return “The changes you made will be lost if you navigate away from this page”;
}

</script>