What is a PHP Session?
The web server does not know who you are or what you do, because the HTTP address doesn’t maintain state. Session variables solve this problem by storing user information to be used across multiple pages (e.g. username, favorite color, etc). By default, session variables last until the user closes the browser.
So; Session variables hold information about one single user, and are available to all pages in one application.
Start a PHP Session
A session is started with the session_start() function.
Session variables are set with the PHP global variable: $_SESSION.
<?php session_start(); $_SESSION['name']="Username"; echo isset($_SESSION['name'])?$_SESSION['name']." is available":"The user not Exist"; ?>
Destroy a PHP Session
To remove all global session variables and destroy the session, use session_unset() and session_destroy():
<?php session_start(); $_SESSION['name1']="Unsername"; session_unset(); session_destroy(); echo isset($_SESSION['name1'])?$_SESSION['name1']." is available":"The user not Exist"; ?>