折叠面板

1. data-toggle="collapse" 添加到您想要展开或折叠的组件的链接上。
2. href 或 data-target 属性添加到父组件，它的值是子组件的 id。
3. data-parent 属性把折叠面板（accordion）的 id 添加到要展开或折叠的组件的链接上。

<div class="panel-group" id="accordion">
  <div class="panel panel-default">
    <div class="panel-heading">
      <h4 class="panel-title">
        <a data-toggle="collapse" data-parent="#accordion" 
          href="#collapseOne">
          点击我进行展开，再次点击我进行折叠。第 1 部分
        </a>
      </h4>
    </div>
    <div id="collapseOne" class="panel-collapse collapse in">
      <div class="panel-body">
        Nihil anim keffiyeh helvetica, craft beer labore wes anderson 
        cred nesciunt sapiente ea proident. Ad vegan excepteur butcher 
        vice lomo.
      </div>
    </div>
  </div>
  <div class="panel panel-default">
    <div class="panel-heading">
      <h4 class="panel-title">
        <a data-toggle="collapse" data-parent="#accordion" 
          href="#collapseTwo">
          点击我进行展开，再次点击我进行折叠。第 2 部分
        </a>
      </h4>
    </div>
    <div id="collapseTwo" class="panel-collapse collapse">
      <div class="panel-body">
        Nihil anim keffiyeh helvetica, craft beer labore wes anderson 
        cred nesciunt sapiente ea proident. Ad vegan excepteur butcher 
        vice lomo.
      </div>
    </div>
  </div>
  <div class="panel panel-default">
    <div class="panel-heading">
      <h4 class="panel-title">
        <a data-toggle="collapse" data-parent="#accordion" 
          href="#collapseThree">
          点击我进行展开，再次点击我进行折叠。第 3 部分
        </a>
      </h4>
    </div>
    <div id="collapseThree" class="panel-collapse collapse">
      <div class="panel-body">
        Nihil anim keffiyeh helvetica, craft beer labore wes anderson 
        cred nesciunt sapiente ea proident. Ad vegan excepteur butcher 
        vice lomo.
      </div>
    </div>
  </div>
</div>

一个实用的折叠导航面板组：

<div class="panel-group" id="accordion">
<div class="panel panel-default">
<div class="panel-heading">
<h4 class="panel-title">
<a data-toggle="collapse" data-parent="#accordion"
href="#collapseOne">
点击我进行展开，再次点击我进行折叠。第 1 部分
</a>
</h4>
</div>
<div id="collapseOne" class="panel-collapse collapse in list-group">

<a href="#" class="list-group-item">免费域名注册</a>
<a class="list-group-item">免费 Window 空间托管</a>
<a class="list-group-item">图像的数量</a>
<a class="list-group-item">24*7 支持</a>
<a class="list-group-item">每年更新成本</a>

</div>
</div>
<div class="panel panel-default">
<div class="panel-heading">
<h4 class="panel-title">
<a data-toggle="collapse" data-parent="#accordion"
href="#collapseTwo">
点击我进行展开，再次点击我进行折叠。第 2 部分
</a>
</h4>
</div>
<div id="collapseTwo" class="panel-collapse collapse list-group">
<a href="#" class="list-group-item">免费域名注册</a>
<a class="list-group-item active">免费 Window 空间托管</a>
<a class="list-group-item">图像的数量</a>
<a class="list-group-item">24*7 支持</a>
<a class="list-group-item">每年更新成本</a>
</div>
</div>
<div class="panel panel-default">
<div class="panel-heading">
<h4 class="panel-title">
<a data-toggle="collapse" data-parent="#accordion"
href="#collapseThree">
点击我进行展开，再次点击我进行折叠。第 3 部分
</a>
</h4>
</div>
<div id="collapseThree" class="panel-collapse collapse list-group">
<a href="#" class="list-group-item">免费域名注册</a>
<a class="list-group-item active">免费 Window 空间托管</a>
<a class="list-group-item">图像的数量</a>
<a class="list-group-item">24*7 支持</a>
<a class="list-group-item">每年更新成本</a>
</div>
</div>
</div>