JS生成数字下拉列表

code:
<html>
<head>
<title></title>
<script language=”javascript">
    //生成数字下拉列表（选中项，起始数字，结束数字）
    function CreateOption(str1, str2, str3) {
        var CreateOption = "";
        for (var i = str2; i <= str3; i++) {
            CreateOption += "<option value=" + i;
            if (str1 == i) {
                CreateOption += "\" selected>" + i + "</option>";
            }
            else {
                CreateOption += "\">" + i + "</option>";
            }
        }
        document.write(CreateOption);
    }
</script>
</head>
<body>
<select >
<script type="text/javascript">CreateOption('1','1','20')</script>
</select>
</body>
</html>