同级框架取值

<%@ Page language="c#" Codebehind="main.aspx.cs" AutoEventWireup="false" Inherits="WebBill.ebsys.zk.main.main"  responseEncoding="gb2312" %>
<HTML>
<HEAD>
<TITLE>正康在线</TITLE>
<script language="javascript">
var pubParams="<%=pubParams%>";
</script>
</HEAD>
<frameset rows="80,80%" frameborder="0" border="0" frameSpacing="5">
<frame id="topWin" name="topWin" src="top.htm" scrolling="no" frameborder="0" resize>
<frameset id="bottomWin" name="bottomWin" cols="20%,80%" frameborder="0" border="0" frameSpacing="5">
<frame id="leftWin" name="leftWin" src="left.htm" scrolling="auto" frameborder="0">
<frame id="rightWin" name="rightWin" src="right.htm" scrolling="auto" frameborder="0">
</frameset>
</frameset>
</HTML>
左框架leftWin中的left.htm通过js语句parent.parent.pubParams取到了父框架的html文件的变量，我右框架取不到左框架html变量，怎么取