Of course, when (*if*) all browsers are HTML5 compliant all you need is javascript and a manifest file : I have already developed an iPhone/iPad 'app' that works offline, connects via ajax to servers to download data and uses HTML 5's own SQL language to manipulate data.
(Also works on safari and chrome on pc, but have not yet fixed some issues on Android phone)
Of course, when (*if*) all browsers are HTML5 compliant all you need is javascript and a manifest file : I have already developed an iPhone/iPad 'app' that works offline, connects via ajax to servers to download data and uses HTML 5's own SQL language to manipulate data.
(Also works on safari and chrome on pc, but have not yet fixed some issues on Android phone)
That should be the way to go!