title: one liquid div with one fixed size div
body: <p>I am trying to build a layout which has a fixed width div and a liquid width div beside it :</p>
  
  <pre><code>&lt;div id="main" style="width:100%; height:500px; background-color: #ccc;"&gt;
      &lt;div id="right" style="float: right; width:100px; height:500px; background-color: red;"&gt;
      &lt;/div&gt;
      &lt;div id="left" style="float: right; width: auto; height:500px; background-color: orange;"&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>the left div is not filling its width, also i want this div to fill whole main div when right div is not present, how can i do it ?</p>