获取URL对应的HTML文档及用正则做replace

        System.Net.WebRequest request = System.Net.WebRequest.Create("http://la.jmw.com.cn/c.asp");
        request.UseDefaultCredentials = false;
        System.Net.WebResponse response = request.GetResponse();
        System.IO.Stream resStream = response.GetResponseStream();
        System.IO.StreamReader sr = new System.IO.StreamReader(resStream, System.Text.Encoding.Default);
        string m_str = System.Web.HttpUtility.HtmlEncode(sr.ReadToEnd());
        Response.Write(m_str);
        System.Text.RegularExpressions.Regex r = new System.Text.RegularExpressions.Regex(@"[^0-9]");
        //m_str = m_str.Replace(r, "");
        if (r.IsMatch(m_str))
        {
            m_str = r.Replace(m_str, "");
        }
        Response.Write(m_str);
        resStream.Close();
        sr.Close();