title: relation between sess_expiration and sess_time_to_update with ajax call in codeIgniter?
body: <p>I'm bit confused about the effect on <code>sess_expiration</code> time with <code>sess_time_to_update</code> in php/codeIgniter, Since my website will never change its url or never refresh/reload the page by itself (everything build in ajax), what will be the effect on <code>sess_expiration</code> in this situation also.</p>
  
  <p>I'm new to php/CodeIgniter simple and detailed explanation about the above will be appreciable. </p>