How to call a function before leaving page with Javascript

Question

I would like to execute a function before leaving page without showing a confirmation popup with Javascript only. I\'ve tried with the code below but it did

Answer 1

What you're doing there is definitely not going to do it. Comparing window.onbeforeunload to true at some arbitrary time doesn't even make sense.

What's with the commented out code at the end? If anything, you need to assign a function to onbeforeunload:

var result = 'test';

window.onbeforeunload = function() {
  result = 'test1';
  alertmess();
}

function alertmess() {
  alert(result);
}

However, the above only appears to work in IE. Please see @Bulk's comment and @Brandon Gano's answer.