Is it possible to display a custom message in the beforeunload popup?

Question

When using window.onbeforeunload (or $(window).on(\"beforeonload\")), is it possible to display a custom message in that popup?

Maybe a sma

Answer 1

All the above doesn't work in chrome at least it need to add return false otherwise nothing happen.

window.onbeforeunload = function(e) {
  $('#leaveWarning').show();

  // the timer is only to let the message box disappear after the user
  // decides to stay on this page
  // set this to 1ms .. since timers are stopped for this modal  
  setTimeout(function() {
    $('#leaveWarning').hide();
  }, 1);

  // 
  return false;
  return "This message is not relevant in most modern browsers.";
}