给div一个class “dropdown”，将下拉菜单放在这个div里就可以显示bootstrap的下拉菜单。

<div class="dropdown">

<button class="btn btn-default dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown">

Dropdown

<span class="caret"></span>

</button>

<ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1">

<li role="presentation"><a role="menuitem" tabindex="-1" href="#">Regular link</a></li>

<li role="presentation" class="disabled"><a role="menuitem" tabindex="-1" href="#">Disabled link</a></li>

<li role="presentation"><a role="menuitem" tabindex="-1" href="#">Another link</a></li>

</ul>

</div>