Untitled

<?php
    $host = "localhost";
    $user = "root";
    $pass = "pass";
    $db = "sheetpal";

    mysql_connect($host, $user, $pass) or die("Could not connect to database");
    mysql_select_db($db);

    if (isset($_POST['username'])){
        $username = $_POST['username'];
        $password = $_POST['password'];

        $username = stripslashes($username);
        $password = stripcslashes($password);

        $sql = "SELECT * FROM users WHERE username = '$username' and password = '$password' ";
        $res = mysql_query($sql);
        if(mysql_num_rows($res) == 1){
            echo "You have successfulyl logged in.";
            exit();
        }
        else {
            echo"Invalid login information.";
            exit();
        }
    }
?>

<html>
<body>
    <form method="post" action="index.php">
    Username: <input type = "text" name = "username" /><br /><br />
    Password : <input type = "password" name = "password" /><br /><br />
    <input type = "submit" name = "submit" value = "Log in" />
    </form>
</body>
</html>