//获取cookie  cname代表你的key比如存储的code就使用code获取值
        function GetCookie(cname) {
            var name = cname + "=";
            var c = document.cookie.split(";");
            for (var i = 0; i < c.length; i++) {
                var ca = c[i].trim();
                //判断是否存在
                if (ca.indexOf(name) == 0) {
                    //正确截取Cookie值
                    return ca.substring(name.length, ca.length);
                }
            }
            return "";
        }