title: unable to extract the value of <img alt> in python
body: <p>I want to extract the brand name from the site <a href="http://www.snapdeal.com/product/aoc-e2060-swn-20-inch/622813?pos=0;85" rel="nofollow">http://www.snapdeal.com/product/aoc-e2060-swn-20-inch/622813?pos=0;85</a>  from the below img tag:</p>
  
  <pre><code>      &lt;img src="http://i1.sdlcdn.com/img/brand/logo/2012-08-01-02-31-15-AOC.jpg" alt="Aoc" width="75" height="45"&gt;
  </code></pre>
  
  <p>i.e, I want to extract "Aoc". I have tried this:</p>
  
  <pre><code>   hxs.select('//*[@id="wrapper"]/div[2]/div[1]/div[3]/div[1]/ul/li[1]/img/@alt').extract()).strip()
  </code></pre>
  
  <p>But I'm getting the null value. Please help.</p>