Untitled

<?php

echo "<html><body>".
	if ($_POST[]) {
		require 'mysql.php';

		$query = "SELECT * FROM `user` WHERE username='$_POST['username']' and password='$_POST['password']'";
		$result = mysqli_query($connection, $query) or die(mysqli_error($connection));
		$count = mysqli_num_rows($result);

		if ($count != 0) {
			echo "You are logged in as " . $_POST['username'];
			<br><br><a href='$_SERVER['PHP_SELF']'>Logout</a>
		}
		else {
			echo 'Invalid username or password.';
		}
	}
."</body></html>";

?>