js获取url参数值

 <script type="text/javascript">
        function GetQueryString(name) {
            var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i");
            var r = window.location.search.substr(1).match(reg);

            if (r != null) {
                return unescape(r[2]);
            }

            return null;
        }

</script>