<?php
session_start();
if ($_SESSION['ref'] == 'checklogin') {
echo "Username or password was incorrect!";
}
$_SESSION['ref'] = 'login';
?>
<html>
<head>
</head>
<body>
<form action="checklogin.php" method="post">
Username: <input type="text" name="uname" />
Password: <input type="password" name="pass" />
<input type="submit" />
</form>
</body>
</html>