<?php
$_SESSION['logged_on'] = false;
$_SESSION['username'] = 'username';
if (empty($_SESSION['logged_on']) || empty($_SESSION['username'])) {
echo 'not logged in code would stop running here if there was a die';
}
$_SESSION['logged_on'] = true;
$_SESSION['username'] = 'username';
if (empty($_SESSION['logged_on']) || empty($_SESSION['username'])) {
echo 'also not logged in code would stop running here if there was a die';
}