title: Replace text in a textarea on button click
body: <p>I'm trying to add a textarea to the sidebar where users can convert text to numbers on button click.</p>
  
  <p>The code is in this jsfiddle: <a href="http://jsfiddle.net/DF5Xf/" rel="nofollow">http://jsfiddle.net/DF5Xf/</a></p>
  
  <p>When I click on the button nothing changes... Is there something that I need to change in the code to make it work?</p>
  
  <p>I have spent an hour looking for a solution...</p>
  
  <p>Thanks</p>