It was stated in http://www.html5rocks.com/en/tutorials/appcache/beginner/
that to attempt to update cache requires the manifest file to have changed. Which means the guy on the server side have to manually change the manifest file every time he want to update what he want to cache.
For testing purposes is there a way for the server side to make manifest editable from client side so the manifest can be changeable by a user so that the user can store whatever he want to store in cache?
Looks like the answer is impossible from client side from this post: Dynamically Trigger HTML5 Cache Manifest file?