Max steps it up a gear and shows us how we can notify the user that they’re offline. This is great to do to make the user aware that the content they are viewing might have been updated, or to give them a list of content that is already in cache so they know what they can view.
Offline support is awesome, however your users might not be aware of these capabilites – and they shouldn’t have to be. In some cases they might not even know that they’ve gone offline. That’s why it’s important to communicate what’s going on.An excerpt from You’re Offline