方式1-列表方式：
<ol class="breadcrumb">
<li class="breadcrumb-item active">Home</li>
</ol>
<ol class="breadcrumb">
<li class="breadcrumb-item"><a href="#">Home</a></li>
<li class="breadcrumb-item active">Library</li>
</ol>
<ol class="breadcrumb">
<li class="breadcrumb-item"><a href="#">Home</a></li>
<li class="breadcrumb-item"><a href="#">Library</a></li>
<li class="breadcrumb-item active">Data</li>
</ol>显示：
举例2：非类别方式
<nav class="breadcrumb">
<a class="breadcrumb-item" href="#">Home</a>
<a class="breadcrumb-item" href="#">Library</a>
<a class="breadcrumb-item" href="#">Data</a>
<span class="breadcrumb-item active">Bootstrap</span>
</nav>显示如下
