public static string DownLoadHtml(string url)
        {
            try
            {
                CookieContainer c = new CookieContainer();
                Uri u = new Uri("http://www.baidu.com");
                CookieCollection ccs = new CookieCollection();
                ccs.Add(new Cookie("BAIDUID", System.Guid.NewGuid().ToString().ToUpper().Replace("-", "") + ":FG=1"));
                c.Add(u, ccs);

                HttpWebRequest r = (HttpWebRequest)WebRequest.Create(url);
                
                //r.Headers["Cache-Control"] = "no-cache";
                //r.Headers["Pragma"] = "no-cache";
                r.UserAgent = @"Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET4.0C; .NET4.0E)";
                r.Accept = @"*/*";
                r.Host = "www.baidu.com";
                r.Headers["Accept-Encoding"] = "gzip, deflate";
                r.Headers["Accept-Language"] = "zh-cn";
                r.Method = "get";
                
                //r.Referer = "http://www.baidu.com";
                r.CookieContainer = c;
                r.AllowAutoRedirect = true;
                HttpWebResponse rep = (HttpWebResponse)r.GetResponse();
                
                Stream receiveStream = rep.GetResponseStream();
      
                string data = string.Empty; 
                string sResponseHeader = rep.Headers["Content-Encoding"]; 
                if (!string.IsNullOrEmpty(sResponseHeader))
                {
                    if (sResponseHeader.ToLower().Contains("gzip"))
                    {
                        byte[] b = DecompressGzip(receiveStream);
                        data = System.Text.Encoding.GetEncoding("gb2312").GetString(b);
                    }
                    else if (sResponseHeader.ToLower().Contains("deflate"))
                    {
                        byte[] b = DecompressDeflate(receiveStream);
                        data = System.Text.Encoding.GetEncoding("gb2312").GetString(b); 
                    }
                }
                //
                RegexOptions options = RegexOptions.None | RegexOptions.Singleline;
                Regex regex = new Regex("<title>(?<title>.*?)</title>", options);
                MatchCollection matches = regex.Matches(data);
                if (matches != null)
                {
                    foreach (Match m in matches)
                    {
                        if (m.Groups["title"].Value.IndexOf("您的访问出错了") >= 0)
                        {
                            data = "err:访问出错，需填写验证码";
                            break;
                        }
                    }
                }
                return data;
            }
            catch(Exception er)
            {
                return "err:"+er.Message;
            }
        }

        private static byte[] DecompressGzip(Stream streamInput)
        {
            Stream streamOutput = new MemoryStrea