Do I have to open a iOS webapp before the app is cached (cache manifest)?

I need clarification.

My webapp is cached in safari. With airplane mode on (wifi off) everything is worki开发者_运维问答ng fine.

When I say "add to homescreen" the app only works when I open it one time with wifi on. After that the app works perfectly well offline.

Is that the expected behavior?

Till now I understood that the cached data (including localStorage stuff) is transfered from safari to the webapp.

Yes, when a web app is added to the home screen, it will no longer be opened using MobileSafari, but using WebSheet. Unless they share the same local storage, it makes sense that you would need to cache the app again after adding it to the home screen.