请教一个RADIO的应用问题

<html>
<head>
<script language=javascript>
function procFun()
{
    disp = open("", "newwendow");
    disp.document.write("<html><body>");
    if (document.form1.rdo1.checked)
    {
        disp.document.write("你选择了R1");
    }
    else
    {
        disp.document.write("你选择了R2");
    }
    disp.document.write("</body></html>");
    document.form1.submit();
}
</script>
</head>
<body>
<form name="form1" action="" method="get">
<input type="radio" name="r1" id="rdo1" value="r1" checked>r1
<input type="radio" name="r1" id="rdo2" value="r2">r2
<input type="button" value="submit" onclick="procFun()">
</form>
</body>
</html>