a

if (mysqli_num_rows($data)!=NULL)
        {
          $row = mysqli_fetch_array($data);
          setcookie ('username', $row['tys_username'],time() + 3600);
          $home_url = 'http://' . $_SERVER['HTTP_HOST'] . dirname($_SERVER['PHP_SELF']) . '/home.php';
          header('Location: ' . $home_url);
           }