Sessions are special kind of variables which are used to store data into that needs to be ‘remembered’ and needs to be accessed from different files. For example: you need to store the username of the logged in user on your website. Once the username is stored into a variable, you do not want the username to be lost when the user reloads the page or goes to another page of your website. Therefore, you can use special variables: sessions. All sessions belong to one array of sessions ( they are sub-variables of the array ): $_SESSION. To create a session variable, you simply create a sub-variable of this array. E.g.:

$_SESSION[‘username’] = “Admin”;

You can access any of your session variables on any page of your website. However, there’s one requirement that has to be fulfilled: you need to activate sessions before you can use them. This can be done by calling the function session_start. This must be done before outputting anything graphical ( e.g. HTML / Text ). For example:

<?php
session_start();

$_SESSION[‘username’] = “Admin”;

//… here goes the rest of your webpage …

echo “Hi there, “.$_SESSION[‘username’].”!”;

?>

Calling the function at the beginning of the file is always good.

Example of usage:

create_session.php

<?php
session_start();

$_SESSION[‘username’] = “Admin”;

?>

Note: You have to run this file to make it create the session.

use_session.php

<?php
session_start();

if(isset($_SESSION[‘username’]) && !empty($_SESSION[‘username’])) {

	$username = $_SESSION[‘username’];

}else{

	$username = “guest”;

}

if($username == “Admin”)) {

	echo “Welcome back, Admin!”;

}else{

	echo “You’re not allowed to be here, “.$username.”!”;

}

?>