フレーム間でフォーム内容の受け渡し

(親ウィンドウ)
<html>
<head>
<title></title>
<title>sample</title>
</head>
<frameset cols="50%,*">
<frame src="left.html" scrolling="yes" name="hidari" id="hidari">
<frame src="right.html" scrolling="yes" name="migi" id="migi">
<noframes>
<body>フレーム使用中</body>
</noframes>
</frameset>
</html>
(left.html)
<html>
<head>
<title></title>
<script type="text/javascript">
<!--
function Cng(){
	var str = parent.hidari.document.fm_left.ip_left.value;
	parent.migi.document.fm_right.ip_right.value = str;
}
//-->
</script>
</head>
<body>
<form name="fm_left">
<input type="text" name="ip_left" value="" size="20">
<input type="button" onClick="javascript:Cng()" value="CLICK!!">
</form>
</body>
</html>
(right.html)
<html>
<head>
<title></title>
<title></title>
</head>
<body>
<form name="fm_right">
<input type="text" name="ip_right" value="" size="20">
</form>
</body>
</html>