徽章（Badges）主要用于突出显示新的或未读的项。如需使用徽章，只需要将 .badge 类加上带有指定意义的颜色类 (如 .badge-secondary) 添加到 <span> 元素上即可。 徽章可以根据父元素的大小的变化而变化:

<div class="container"><h2>徽章</h2><h1>测试标题 <span class="badge badge-secondary">New</span></h1><h2>测试标题 <span class="badge badge-secondary">New</span></h2><h3>测试标题 <span class="badge badge-secondary">New</span></h3><h4>测试标题 <span class="badge badge-secondary">New</span></h4><h5>测试标题 <span class="badge badge-secondary">New</span></h5><h6>测试标题 <span class="badge badge-secondary">New</span></h6>
</div>

<div class="container"><h2>各种颜色类型的徽章</h2><span class="badge badge-primary">主要</span><span class="badge badge-secondary">次要</span><span class="badge badge-success">成功</span><span class="badge badge-danger">危险</span><span class="badge badge-warning">警告</span><span class="badge badge-info">信息</span><span class="badge badge-light">浅色</span><span class="badge badge-dark">深色</span>
</div>

使用 .badge-pill 类来设置药丸形状徽章:

<div class="container"><h2>药丸形状徽章</h2><span class="badge badge-pill badge-default">默认</span><span class="badge badge-pill badge-primary">主要</span><span class="badge badge-pill badge-success">成功</span><span class="badge badge-pill badge-info">信息</span><span class="badge badge-pill badge-warning">警告</span><span class="badge badge-pill badge-danger">危险</span>
</div>

<div class="container"><h2>徽章嵌入到按钮内</h2><button type="button" class="btn btn-primary">Messages <span class="badge badge-light">4</span></button><button type="button" class="btn btn-danger">Notifications <span class="badge badge-light">7</span></button>
</div>