title: Return null in HtmlAgilityPack
body: <p>I want use this code but it returns NULL in all this parameters ! would you please help how to fix it or what is the problem ?</p>
  
  <p><a href="http://i.stack.imgur.com/6bHcS.png" rel="nofollow">click here</a> for a picture that shown what happened.</p>
  
  <p>code :</p>
  
  <pre><code>    HtmlWeb hw = new HtmlWeb();
  
      private void button1_Click(object sender, EventArgs e)
          {
              Crawler("http://www.avval.ir/directory", 0);
          }
  
      public void Crawler(string url, int pid)
          {
  
  
              try
              {
  
                  HtmlAgilityPack.HtmlDocument doc = hw.Load("http://www.avval.ir/directory");
                  HtmlNodeCollection nodes = doc.DocumentNode.SelectNodes("//a[@class='metatag-topi metatag-keywords']");
                  HtmlNodeCollection nodes2 = doc.DocumentNode.SelectNodes("//div[@class='pagination']/a[@href]");
                  HtmlNodeCollection phone = doc.DocumentNode.SelectNodes("//p[@class='phone fRight ml10']");
  
              }
          }
  </code></pre>