<li>Storing the initial pre-enhanced version of the web page so that it can act as a "conforming alternate version" for any later enhanced versions of the content; and</li>
         <li>Inserting a mechanism into all enhanced versions of the web page which allows a user to revert the content back to the stored pre-enhanced Alternate Version.</li>
      </ol>
<p>Web pages designed with progressive enhancement detect features in the web-enabled accessing device (size, capability and software) to allow those s