 <p>If you can find out the first and last values of the labels and store them in variables before itself, then you can do some thing like this <a href="http://jsfiddle.net/E7GBd/" rel="nofollow">http://jsfiddle.net/E7GBd/</a> using </p> <pre><code>formatter: function(){} </code></pre> <p>Hope this will help you.</p>