Bootstrap 折叠（Collapse）插件

<div  class="panel-group" role="tablist" id="accordion" aria-multiselectable="false" >
<div class="panel panel-default">
<div class="panel-heading" role="tab" id="headingSubject">
<h4 class="panel-title">
<a data-toggle="collapse" data-parent="#accordion" aria-expanded="true" href="#collapseSubject" aria-controls="collapseSubject">这是个Panel</a>
</h4>
</div>
<div class="panel-collapse collapse" id="collapseSubject" role="tabpanel" aria-labelledby="headingSubject">
<div class="panel-body">
<div class="form-group">
<div class="col-md-6">
<a href="@Url.Action("Index","Home")">About</a>
</div>
<div class="col-md-6">
<a href="~/Views/Home/Contact.cshtml">Contact</a>
</div>
</div>
</div>
</div>
</div>
</div>