How to use PHP $_SESSION

Here's a simple guide on how to use the PHP $_SESSION to keep the data from one page to another.

1st page
=======
<?php
session_start();$_SESSION["a1"] = "LOGGED";?>

2nd page
=======
<?php
session_start();
echo $_SESSION["a1"];?>

Visit php.net for additional information.
http://www.php.net/manual/en/reserved.variables.session.php