使下拉菜单向上而不是向下展开。
<div class="@(6)">
<button data-toggle="dropdown"
class="btn btn-primary dropdown-toggle">
Dropdown Example
<span class="caret"></span></button>
<ul class="dropdown-menu">
<li><a href="#">HTML</a></li>
<li><a href="#">CSS</a></li>
<li><a href="#">JavaScript</a></li>
</ul>
</div>
<div class="dropup">
<button data-toggle="dropdown"
class="btn btn-primary dropdown-toggle">
Dropdown Example
<span class="caret"></span></button>
<ul class="dropdown-menu">
<li><a href="#">HTML</a></li>
<li><a href="#">CSS</a></li>
<li><a href="#">JavaScript</a></li>
</ul>
</div>