如何在父窗口中得知window.open()出的子窗口关闭事件

复制代码 代码如下:

<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>