<?php session_start();
$username='cwarn23';
$password='password';
if (isset($_POST) && !empty($_POST)) {
if ($_POST['user']==$username && $_POST['pass']==$password) {
$_SESSION['user']=$username;
}
}
if (isset($_SESSION['user'])) {
echo 'You are logged in.';
} else {
echo 'Please log in<br><form method="POST">Username: <input type="text" name="user"><br>Password: <input type="text" name="pass"></form>';
}