Session support in PHP consists of a way to preserve certain data across subsequent accesses. This enables you to build more customized applications and increase the appeal of your web site.
A visitor accessing your web site is assigned a unique id, the so-called session id. This is either stored in a cookie on the user side or is propagated in the URL.
Session Example in PHP:
Source : session_start
//print stored values
echo $_SESSION[‘favcolor’]; // green
echo $_SESSION[‘animal’]; // cat
echo date(‘Y m d H:i:s’, $_SESSION[‘time’]);
// Unset all of the session variables.
$_SESSION = array();
// Finally, destroy the session.