I'm thinking of developing an iPhone app using HTML5 because I don't have mac and not planning to own one, so learning Objective-C would be pointless.
The other reason why I want to use HTML5 is because it's a cross-platform (albeit it depends on the browser). Anyway, I know you can use WebSQL in HTML5 to store offline data, but is it possible to keep a backup of the db? And is it possible to restore it as well?
Yes you can. I do not know if we can do it in code, but you can make a backup manual ways. To do this, simply make a copy of the folder containing the db. On Mac, this folder is located: / Users / [user name] / Library/Safari/Databases/file_0 / On PC, you must activate the option to see hidden folders. Once done, the file is located at this location: C: \ Users \ [user] \ AppData \ Local \ Apple Computer \ Safari \ Databases \ file_0 \
Hoping to have helped you!
Good luck!