1 year ago, I've made a PHP social network which works pretty well. Via browser, once the user logs in, i use the $_SESSION variable to store credentials and remember the user through all pages. Everything works well.
Now i'm trying to build the app version of the website, using Phonegap and jQuery Mobile. At first glance i tried to use the same approach: to manage user login i implemented a simple form with Email and Password, which sends an ajax request to a "check_login.php" file. If email and pw are correct, i "login the user", which simply means i store everything in the session variable, as i always did.
What i noticed, which is driving me crazy, is that using this approach data are not being stored into the $_SESSION variable. Using my app, each time I send an AJAX request to the server, the $_SESSION variable is gone and it looks like login data are not stored. Like i never logged in. (Of course, i've put session_start() at the top of each page). Moreover, each time i send an AJAX request to the server, the session_id() changes.
Is that normal? Does this mean with Phonegap i can't rely on $_SESSION variable or I am just missing something? If yes, why?