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<!doctype html>
<html lang="en">
  <head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="css/bootstrap.min.css">

    <!-- Ambil dari CDN JQUERY-->
    <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"></script>

    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js"></script>

    <!-- Bootstrap JS -->
    <script src="js/bootstrap.min.js"></script>

  </head>

  <body>
    <div class="btn-group" role="group" aria-label="Button group with nested dropdown">
  <button type="button" class="btn btn-secondary">1</button>
  <button type="button" class="btn btn-secondary">2</button>

  <div class="btn-group" role="group">
    <button id="btnGroupDrop1" type="button" class="btn btn-secondary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
      Dropdown
    </button>
    <div class="dropdown-menu" aria-labelledby="btnGroupDrop1">
      <a class="dropdown-item" href="#">Dropdown link</a>
      <a class="dropdown-item" href="#">Dropdown link</a>
    </div>
  </div>
</div>
  </body>
</html>