title: Scanning each HTML node with nokogiri
body: <p>How can we scan each element and sub-element of an HTML document with Nokogiri, and testing for each one if the current tag is a block?</p>
  
  <p>According to <a href="http://wiki.github.com/tenderlove/nokogiri/examples" rel="nofollow noreferrer">http://wiki.github.com/tenderlove/nokogiri/examples</a>, we can test if an element is a block using:</p>
  
  <pre><code>element[:class] == "block"
  </code></pre>
  
  <p>But I don't see how to scan and test each HTML ones...</p>
  
  <p>Thanks.</p>