function getInnerText(elt) {
	var _innerText = elt.innerText;
	if (_innerText == undefined) {
  		_innerText = elt.innerHTML.replace(/<[^>]+>/g,"");
	}
	return _innerText;
}

var text = elt.innerText;

var text = getInnerText(elt);

<input type="button" value="Close" onclick="CloseWindow();" />
<script type='text/javascript'>
<!--
function CloseWindow() {
	ww = window.open(window.location, "_self");
	ww.close();
} 
-->
</script>

window.onbeforeunload = function (evt) {
  var message = 'Are you sure you want to leave?';
  if (typeof evt == 'undefined') {
    evt = window.event;
  }
  if (evt) {
    evt.returnValue = message;
  }
  return message;
}