Hi, you can use json, no need to use jsonp. When you package an app with Phonegap there is no cross domain problem because you haven't a "starting url". I suggest to use server side session variable, is what i do. Once you login you can check the validity of the session variable at every ajax call. If you dont have ajax call after login just check the validity of session variable at regular interval (setInterval) with a an ajax call to the server.