title: Calculate the grid column value with total value in extjs4.1
body: <p>I have the grid with two columns: Target and Target Percentage. I am getting Target value from store. I need to calculate Total and Target percentage value using Jan/Total Jan*100. I want a summary for target %. Can anybody tell me how to do this?</p>
  
  <p>I need to calculate the total manually </p>
  
  <p>E.g </p>
  
  <pre><code>Month  Target      Target %
     Jan     50       **50/100*100**
     Mon     50       50/100*100
     Total   100        
  </code></pre>
  
  <p>Thanks</p>