@saeed Thanks, I'm not sure about the discrepancy between my testing and the der-schepp site I'm afraid. I actually need to do a follow up post in general about AppCache as it is now technically deprecated: http://caniuse.com/#feat=offline-apps Personally I found far too many issues cross-browser to ever use it for final production code. The newer Service Workers http://caniuse.com/#feat=serviceworkers appears to be a lot more powerful, but unfortunately at the time of writing only support by Firefox, Chrome and Opera. However, Microsoft intend adding it very soon and WebKit devs have it under consideration.