How to use PHP Session.

Start with start_session() command. It needs to be include on every PHP page that will use session. You can pass the variables between PHP pages using the global $_SESSION variable. When you are done with the session, unset the $_SESSION variable and call session_destroy() command.

page1.php
<?php
    start_session();
    $_SESSION['valid_user'] = 'Me';
?>

page2.php
<?php
    start_session();
    if ( isset($_SESSION['valid_user'] ) {
        print 'hello ' . $_SESSION['valid_user'];
    } else {
        print 'hello nobody';
    }
    // close session
    // don't do this: $_SESSION = array();
    unset($_SESSION['valid_user'];
    session_destroy();
}
?>