title: Parse HTML doc with HtmlAgilityPack-Xpath, RegExp
body: <p>I try parse image url from html with HtmlAgilityPack.  In html doc I have img tag :</p>
  
  <pre><code>&lt;a class="css_foto" href="" title="Fotka: MyKe015"&gt;
     &lt;span&gt;
        &lt;img src="http://213.215.107.125/fotky/1358/93/v_13589304.jpg?v=6" 
             width="176" height="216" alt="Fotka: MyKe015" /&gt;
     &lt;/span&gt;
  &lt;/a&gt;
  </code></pre>
  
  <p>I need get from this img tag atribute src. I need this: <strong>http://213.215.107.125/fotky/1358/93/v_13589304.jpg?v=6.</strong></p>
  
  <p>I know this:</p>
  
  <ol>
  <li>Src atribute consist url, url start
  with
  <strong>http://213.215.107.125/fotky</strong> </li>
  <li>I know value of alt atribute Url
  have
      variable lenght and also html doc
      consist other img tags with url, which start with
      <strong>http://213.215.107.125/fotky</strong></li>
  <li>I know alt attribute of img tag (Fotka: Myke015))</li>
  </ol>
  
  <p>Any advance, I try many ways, but nothing works good.</p>
  
  <p>Last I try this:</p>
  
  <pre><code>    List&lt;string&gt; src;
  
      var req = (HttpWebRequest)WebRequest.Create("http://pokec.azet.sk/myke015");
      req.Method = "GET";
  
      using (WebResponse odpoved = req.GetResponse())
      {
          var htmlDoc = new HtmlAgilityPack.HtmlDocument();
          htmlDoc.Load(odpoved.GetResponseStream());
  
          var nodes = htmlDoc.DocumentNode.SelectNodes("//img[@src]");
          src = new List&lt;string&gt;(nodes.Count);
  
          if (nodes != null)
          {
              foreach (var node in nodes)
              {
                  if (node.Id != null)
                      src.Add(node.Id);
              }
          }
      }
  </code></pre>