if($stmt->rowCount() > 0){
    // get retrieved row
    $row = $stmt->fetch(PDO::FETCH_ASSOC);
    // create array
    $user_arr=array(
        "status" => true,
        "message" => "Successfully Login!",
header( 'Location: ./index.html' ),
        "id" => $row['id'],
        "username" => $row['username']

    );