public partial class sina : System.Web.UI.Page

 {

     protected string ip = "171.216.18.89";

     protected void Page_Load(object sender, EventArgs e)

     {

         //if (IPOperation.GetIP() != "127.0.0.1")

         //{

         //    ip = IPOperation.GetIP();

         //}

         this.ClientScript.RegisterStartupScript(this.GetType(), "message", "<script language='javascript' defer>alert('" + GetCityByIP(ip).ToString() + "');</script>");

     }

     private string GetCityByIP(string ip)

     {

         string cityName = "成都";

         if (!string.IsNullOrEmpty(ip))

         {

             string url = "http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=js&ip=" + ip;

             HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;

             request.Method = "POST";

             request.ContentType = "application/json;charset=utf-8";

             Stream stream = request.GetResponse().GetResponseStream();

             StreamReader sr = new StreamReader(stream, Encoding.UTF8);

             string str = sr.ReadToEnd().Split('=')[].ToString().TrimEnd(';');

             IPArea list = new JavaScriptSerializer().Deserialize<IPArea>(str);

             cityName = list.city;

         }

         return cityName;

     }

 }

 class IPArea

 {

     public int ret { get; set; }

     public string start { get; set; }

     public string end { get; set; }

     public string country { get; set; }

     public string province { get; set; }

     public string city { get; set; }

     public string district { get; set; }

     public string isp { get; set; }

     public string type { get; set; }

     public string desc { get; set; }

 }