Switching between Full/Plain HTML view and setting default view
<p>I am developing a website that has a plain HTML version for older browsers (I know this is not a good practice, but my employers insisted). </p>

<p>I put a link on the footer of all pages to switch between the views. Then I use a session variable to store whether the user is in the Full Site mode or the Plain Site mode.</p>

<p>However, this session variable does not get destroyed when a user quit the website. Since I want the site to show the Full Site version by default, this is a problem. I don't want the Plain Site mode to be "remembered". But it is not possible to do a destroy_session() on page exit without javascript, and it would be inefficient.</p>

<p>Any ideas on how I can fix this problem?</p>
