What kind of local storage is supported? Does 'setPreference' for key work or is there support for local database and is it possible to store other content (images and stuff the app loads from internet) on the device?
// Store objects to local storage
var jsonTasks = JSON.stringify( tasks );
localStorage.tasks = jsonTasks;
// Read objects from local storage
tasks = JSON.parse( localStorage.tasks );
HTML 5 local storage is supported. Also, you can use the file system API to access the local file system.