bootstrapt用button和ul做下拉菜单

<div class="dropdown">
    <button  id="scaleToggle" class="btn btn-default dropdown-toggle" type="button" id="dropdownScale" data-toggle="dropdown" aria-haspopup="true" aria-expanded="true">
     规模
       <span class="caret"></span>
    </button>
    <ul class="dropdown-menu" aria-labelledby="dropdownScale">
       <li class="scale-item" data-value="0"><a>1-10人</a></li>
       <li class="scale-item" data-value="1"><a>11-50人</a></li>
       <li class="scale-item" data-value="2"><a>51-250人</a></li>
       <li class="scale-item" data-value="3"><a>251-500人</a></li>
       <li class="scale-item" data-value="4"><a>大于500人</a></li>
    </ul>
</div>