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 .bg-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:
<h1>测试标题 <span class="badge bg-secondary">New</span></h1>
<h2>测试标题 <span class="badge bg-secondary">New</span></h2>
<h3>测试标题 <span class="badge bg-secondary">New</span></h3>
<h4>测试标题 <span class="badge bg-secondary">New</span></h4>
<h5>测试标题 <span class="badge bg-secondary">New</span></h5>
<h6>测试标题 <span class="badge bg-secondary">New</span></h6>
以下列出了所有颜色类型的徽章:
<span class="badge bg-primary">主要</span>
<span class="badge bg-secondary">次要</span>
<span class="badge bg-success">成功</span>
<span class="badge bg-danger">危险</span>
<span class="badge bg-warning">警告</span>
<span class="badge bg-info">信息</span>
<span class="badge bg-light">浅色</span>
<span class="badge bg-dark">深色</span>
使用 .rounded-pill 类来设置药丸形状徽章:
<span class="badge rounded-pill bg-default">默认</span>
<span class="badge rounded-pill bg-primary">主要</span>
<span class="badge rounded-pill bg-success">成功</span>
<span class="badge rounded-pill bg-info">信息</span>
<span class="badge rounded-pill bg-warning">警告</span>
<span class="badge rounded-pill bg-danger">危险</span>
以下实例将徽章嵌入到按钮内：
<button type="button" class="btn btn-primary">
Messages <span class="badge bg-light">4</span>
</button>