Java script is not working in Chrome

The code below works fine on IE and FF but not on Google Chrome. 
Please can someone help me to find out the mistake?.Thanks In Advance.

Flex Code: 
Public function init():void
{
ExternalInterface.addCallback("getCloseConfirmMessage", closeConfirmMessage);
	
ExternalInterface.call("setUpBeforeUnload",FlexGlobals.topLevelApplication.id);
}
Public function closeConfirmMessage():void
{
	//DB updation code  
}

Java Script :
  <script language="javascript" type="text/javascript">
    var fxControl;
    function confirmClose()
    {
alert("Please click OK to end the session");                             fxControl.getCloseConfirmMessage();
    };
    function setUpBeforeUnload( appName )
    {
        fxControl = document[ appName ] || window[ appName ];
window.onbeforeunload = confirmClose;
    };

</script>