//c# code

        public string testcookie(string id)
        {
            HttpCookie Cookie;
            Cookie = Request.Cookies["testcookie"];
            string GotoDomain = System.Configuration.ConfigurationManager.AppSettings["GotoDomain"].ToString();
            if (string.IsNullOrEmpty(id))//读取
            {
                string test1 = "";
                if (Cookie != null)
                {
                    test1 = Common.OperateText.Decrypt(Cookie["test1"].ToString());
                }
                return ("{\"读取到的test1\":\"" + test1 + "\",\"code\":\"200\"}");
            }
            else//写入
            {
                Cookie = new HttpCookie("testcookie");
                string test1 = id + "-" + DateTime.Now + GotoDomain;
                Cookie["test1"] = Common.OperateText.Encrypt(test1);
                Cookie.Domain = GotoDomain;
                Cookie.Path = "/";
                Cookie.Secure = false;
                Cookie.Expires = DateTime.Now.AddHours(24);
                Response.Cookies.Add(Cookie);
                return ("{\"写入的test1\":\"" + test1 + "\",\"code\":\"200\"}");

            }

        }

//配置成两个网站

如果子站点间cookie始终不能跨域，那就是web服务器配置的问题，我就遇到过这种问题。这种问题应该多尝试配置服务器。