function keyPressed(evt) {

var ESC = 27;
//var F11 = 122;
if(document.layers)
{
	alert(evt.which);
	if (evt.which == ESC)
	 {
		return false;
	 }
}
else if(document.all)
{
 //alert(event.keyCode);
 if (event.keyCode == ESC)
  {
		event.keyCode = 0;
		window.event.returnValue = false;
  }
}

}
if(document.layers){
document.captureEvents (Event.KEYDOWN);
}
document.onkeydown=keyPressed;