title: How to extend datatables sorting functions for multi rows levels support
body: <p>I have the next table structure:</p>
  
  <p><a href="http://postimage.org/image/bq53yh8q1/" rel="nofollow">Table structure image</a></p>
  
  <p>As you can see there is some levels (3) in this table. I want to sort this table by levels: </p>
  
  <ol>
  <li>Sort first levels (PC and Mobile phones) </li>
  <li>Inside first levels sort second levels (resolutions) </li>
  <li>Inside seond levels sort third levels (os name) etc.</li>
  </ol>
  
  <p>I am forming this table from three objects (object['0']['data'], object['1']['data'] and object['2']['data']).</p>
  
  <p>I used my own js library for this before, but now need switch to datatables.</p>
  
  <p>Old code was like this</p>
  
  <pre><code>//Sort Level 1
      table_data.sort( sorter )
  
      // Sort Level 2
      for (var i in table_data) {
  
          table_data[i].data.sort( sorter );
  
          // Sort Level 3
          for (var j in table_data[i].data) {
              table_data[i].data[j].data.sort( sorter );
          }
      }
  </code></pre>
  
  <p>How to implement this using datatables plugin?</p>