function getHighscore()
{
    if (isset($_GET["graph_id"])) {
        $graphId = $_GET["graph_id"];
        if ($graphId < 1 || $graphId > 9) {
            echo "invalid graph ID!";
            return;
        }
        $database = new Database();
        $stmt = $database->getTop10Score($graphId);
        echo json_encode($stmt);
    } else {
        echo "Wrong parameters for get highscore!";
        return;
    }
}