title: Hiding Modal popup extender from client side
body: <p>I need to hide the modal popup on client using javascript.</p>
  
  <p>if I use  </p>
  
  <pre><code>$find('ModalPopupExtender1').hide();
  </code></pre>
  
  <p>for hiding it is throwing an error saying</p>
  
  <blockquote>
    <p>'null' is null or not an object'</p>
  </blockquote>