HTML 5 offline logic is encapsulated in window.applicationCache object. However it looks like it's not possible to programmatically clear cache data, for example, when user logs off from the system. Is there any other way to clear HTML 5 application cache, except for generating empty manifest file?
Setting aside the specifics of the HTML5 appcache, clearing a browser's cache programmatically has never been possible (beyond certain ActiveX controls for that browser) so I suspect you may come up empty on this one. Perhaps you should focus on the cache control meta tag and test further with your empty manifest idea?