Hi,
solution was found it, which was test it with IE, Firefox, and Chrome. Only thing which developer should do about testing with Firefox, and Chrome is to turn off Blocking Pop Up option under browsers settings.
<pre lang="Javascript">
window.onbeforeunload = confirmExit;
function confirmExit() {
return "You have attempted to leave this page?";
}
var newWindowOpen;
function openPopup() {
newWindowOpen= window.open("URL", "", "");
}
<script>