In my testing, you don’t need to fully embrace HTML5 markup to take advantage of the “offline” functionality, you simply need to add the attribute and related files to your existing website/page. Any modern browser that supports HTML5 should automatically recognize the offline content and use it when appropriate, unfortunately no version of MSIE yet supports this.
In that file, you must then specify the offline behavior, something like this is a good start:
#This is to provide minimal HTML5 offline capabilities
#MIME mapping must be 'appcache=text/cache-manifest'
#Reference to this file is per page, you can have different ones in an app.
#Common image files and css may be 'cached'
On the server side, you’ll have to serve up that file with the appropriate MIME type (
text/cache-manifest, for ApacheHTTPD you simply need to add one line to httpd.conf:
AddType text/cache-manifest .appcache