<div class="btn-group">
  <button type="button" class="btn btn-primary">Test</button>
  <button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
    <span class="sr-only"></span>
  </button>
  <ul class="dropdown-menu" role="menu">
 
<li><a href="link1.php">Link 1</a></li>
 
<li><a href="link2.php">Link 2</a></li>
</ul></div>