大家看看我这个showModalDialog内select的值怎么返回给opener的select？

我在body.htm上打开selUser.htm，现在想把selUser内的select所有的值返回给body.htm内的select，请问返回和怎么接收的函数怎么写？

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body.htm - 接收值的函数怎么写？

<html><head></head>
<script language="JavaScript">
function openwin(srcFile,obj,winFeatures)
{
window.showModalDialog(srcFile, obj, winFeatures);
}
</script>

<body>
<form action="" method="get" name="myForm">
<select name="selUser" size="4" multiple style="width:400px"></select>
<input type=button value=" 添加 " onclick="window.openwin('selUser.htm',myForm,'status:no;scrollbars:yes;help:no;dialogleft:400px;dialogtop:300px;dialogwidth:600px;dialogheight:400px')">
</form>
</body></html>

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selUser.htm - 传递值的函数怎么写？

<html><head></head>
<script language="JavaScript">
function AddUser()
{
//opener.addSel();
window.close();
}
</script>

<body>
<form action="" method="get" name="myForm">
<select name="selUser" size="3" multiple style="width:400px">
<option value="1">aaa</option>
<option value="2">bbb</option>
<option value="3">ccc</option>
</select>
<input name="button" type=button onclick="AddUser()" value="　确认　">
</form>
</body></html>