Help on RMS 11g forms alerting

Currently we are using the piece of code below in webutiljpi.htm to notify the user to close the RMS screen when he/she tries to exit via internet explorer.

<script language="JavaScript">

window.onbeforeunload=confirm;

function confirm() {

event.returnValue = "Closing RMS Forms Application. Any unsaved changes will be lost! OK to Continue with close ?";

}

</script>

However, the message still shows when clicking "x" in internet explorer even though user closed RMS screen properly.

Do you have any advise so that the message will only show if RMS is actually closed?