Not a web technology expert, but apparently the appcache feature is deprecated (https://developer.mozilla.org/en-US/docs/Web/HTML/Using_the_...) and this dead horse has already been beaten to... er, death? before (http://alistapart.com/article/application-cache-is-a-doucheb...).

I could be missing something, though.

EDIT:

Forgot to mention that both links come straight from that article.