parent.htm :
<html><body>
<p> </p>
<form name=fm_info>
<input type=text name=txtvalue>
</form>
<script language=javascript>
var timer
var winopen
function ifwindowclosed() {
if (winopen.closed == true) { document.fm_info.txtvalue.value="child closed"
window.clearinterval(timer)
}
}
</script>
<input type=button name=btnopen value=open>
<script language=javascript for=btnopen event=onclick>
document.fm_info.txtvalue.value=""
winopen=window.open("child.htm","","toolbar=no, location=no, directories=no, status=no, menubar=no" )
timer=window.setinterval("ifwindowclosed()",500);
</script>
</body></html>
------------------
there can be anything in child.htm