make the back button work in the frontend
usual ajax problem: loading new pages with ajax makes the history of the browser useless => the back button won't work.
so we have to fill the history with every new page loaded through ajax. see: http://www.onjava.com/pub/a/onjava/2005/10/26/ajax-handling-bookmarks-and-back-button.html http://ajaxpatterns.org/Unique_URLs http://www.contentwithstyle.co.uk/Articles/38/fixing-the-back-button-and-enabling-bookmarking-for-ajax-apps http://dev2dev.bea.com/pub/a/2006/01/ajax-back-button.html
etc.