<ul class="nav nav-tabs">
  <li class="nav-item">
    <a class="nav-link <?php if($tabid==1){echo 'active';}?>" href="index">Laporan Penjualan</a>
  </li>
  <li class="nav-item">
    <a class="nav-link <?php if($tabid==2){echo 'active';}?>" href="index-2">Laporan Stok</a>
  </li>
</ul>