title: calculate area of a drawn polygon on google map javascript
body: <p>Hi there I have to calculate the area of drawn polygon on google map . 
  jsfiddle <a href="http://jsfiddle.net/tvqzd/4/" rel="nofollow">http://jsfiddle.net/tvqzd/4/</a></p>
  
  <p>I calculate it using </p>
  
  <pre><code>var area = google.maps.geometry.spherical.computeArea(newShape.getPath()); 
  </code></pre>
  
  <p>but I want it to be Calculated on button click</p>
  
  <p>and polygon is editable . What if I change/edit area ? Can I get the area on areachange event or something?</p>