if (isSet($_POST["register"])) {
        $username = $_POST["username"];
        $password = md5(md5("CgqM87".$_POST["password"]."CgqM87"));
        $passwordr = md5(md5("CgqM87".$_POST["passwordr"]."CgqM87"));
        $email = $_POST["email"];
        $emailr = $_POST["emailr"];
        if (strlen($username) >= 6) {
            $qu = mysqli_query($con, "SELECT * FROM users WHERE username='$username'");
            if (mysqli_num_rows($qu) <= 0) {
                if ($password == $passwordr) {
                    if ($email == $emailr) {
                        $sqli = "INSERT INTO users (username, password, email)
                        VALUES ('$username', '$password', '$email')";
                        if ($con->query($sqli) == TRUE) {
                            echo "<script>alert('User registered, confirmation sent to $email.')</script>";
                            header("Refresh:0");
                        }
                        else
                            echo "<script>alert('Failed to create user.')</script>";
                    }
                    else
                        echo "<script>alert('Emails do not match.')</script>";
                }
                else
                    echo "<script>alert('Passwords do not match.')</script>";
            }
            else
                echo "<script>alert('Username already taken.')</script>";
        }
        else
            echo "<script>alert('Username must at least contain 6 characters.')</script>";
    }