title: Not able to extend liferay session programatically
body: <p>I have been looking for a solution using which I can extend the liferay session when I do AJAX calls on my page. I found out that we can use Liferay.session.extend() to extend the liferay session. This I found out at <a href="https://stackoverflow.com/questions/9509960/extend-session-of-liferay-when-performing-ajax-call">extend session of Liferay when performing AJAX call</a></p>
  
  <p>But am not able to call the extend method, in console I get the error Liferay.session is not defined. </p>
  
  <p>What would be the problem?</p>