title: float : left and clear : right
body: <p>I want to diplay three div like this:</p>
  
  <pre><code>[1]    
  [2][3]
  </code></pre>
  
  <p>The three div have style: <code>float: left</code><br>
  The div 1 have: <code>clear: right</code></p>
  
  <p>Ok I just to put <code>clear: left</code> on div <code>[2]</code>, but if this div is optional?</p>