title: Remove session variable when user leaves page
body: <ol>
  <li><p>I have a page that sets a session variable to hold a list of lookups from the database for the page when the page is loaded.  </p></li>
  <li><p>The page also will need to access that list of lookups when Ajax calls are made from the browser.  </p></li>
  </ol>
  
  <p>I'd like to not load the list of lookups from the database for each Ajax call, but I would like to remove the list of lookups from the session if the user leaves the page.  Is there a best practice or recommended strategy for doing this?</p>