作为额外元素的按钮式下拉菜单

<div class="row">
  <div class="col-lg-6">
    <div class="input-group">
      <div class="input-group-btn">
        <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" aria-expanded="false">Action <span class="caret"></span></button>
        <ul class="dropdown-menu" role="menu">
          <li><a href="#">Action</a></li>
          <li><a href="#">Another action</a></li>
          <li><a href="#">Something else here</a></li>
          <li class="divider"></li>
          <li><a href="#">Separated link</a></li>
        </ul>
      </div>
      <input type="text" class="form-control" aria-label="...">
    </div>
  </div>
  <div class="col-lg-6">
    <div class="input-group">
      <input type="text" class="form-control" aria-label="...">
      <div class="input-group-btn">
        <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" aria-expanded="false">Action <span class="caret"></span></button>
        <ul class="dropdown-menu dropdown-menu-right" role="menu">
          <li><a href="#">Action</a></li>
          <li><a href="#">Another action</a></li>
          <li><a href="#">Something else here</a></li>
          <li class="divider"></li>
          <li><a href="#">Separated link</a></li>
        </ul>
      </div>
    </div>
  </div>
</div>