<nav class="navbar navbar-expand-lg navbar-light bg-light">
  
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>

  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mx-auto">
      <li class="nav-item active">
        <a class="nav-link" href="/main.php">Home <span class="sr-only">(current)</span></a>
      </li>
      
      
      
      <li class="nav-item">
        <a class="nav-link" href="/clients/show.php">Kundenverwaltung</a>
      </li>
      
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Benutzerverwaltung
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
          <a class="dropdown-item" href="/users/show.php?status=0">Benutzer - aktiv</a>
          <a class="dropdown-item" href="/users/show.php?status=1">Benutzer - inaktiv</a>
        </div>
      </li>
      <?php
        if (isset($_GET['uuid'])) {
          $_GET['id']                         = $_GET['uuid'];
        } elseif (isset($_GET['client_uuid'])) {
          $_GET['id']                         = $_GET['client_uuid'];
        }
      ?>
      
      <li class="nav-item">
        <a class="nav-link" href="/clients/search.php?client_uuid=<?php echo $_GET['id']; ?>">Suche</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="/users/change-pw.php">Passwort ändern</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="/Auth/logout.php">Logout</a>
      </li>
  </div>
</nav>