如何在Bootstrap 5网页中创建Web元素间的连接线？

你可以通过CSS伪元素或者自定义div结合Bootstrap的布局类来实现元素间的连接线，下面针对你提供的卡片示例，给出两种常见的实现方式：

方式一：用CSS伪元素实现简单连线 #

适合添加水平线、竖线这类基础连接线，无需额外HTML结构，代码更简洁：

修改后的卡片代码 #

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.2.3/dist/css/bootstrap.min.css" integrity="sha384-rbsA2VBKQhggwzxH7pPCaAqO46MgnOM80zW1RWuH61DGLwZJEdK2Kadq2F9CUG65" crossorigin="anonymous">

<style>
/* 标题与列表之间的水平线 */
.card-title-divider {
  position: relative;
  margin-bottom: 1.5rem;
}
.card-title-divider::after {
  content: "";
  position: absolute;
  bottom: -0.75rem;
  left: 0;
  width: 100%;
  height: 1px;
  background-color: var(--bs-border-color); /* 匹配Bootstrap默认边框色 */
}

/* 列表项左侧的竖线 */
.list-group-item-with-line {
  position: relative;
  padding-left: 1.75rem;
}
.list-group-item-with-line::before {
  content: "";
  position: absolute;
  left: 0.75rem;
  top: 0;
  bottom: 0;
  width: 2px;
  background-color: var(--bs-primary); /* 使用Bootstrap主色调 */
}
/* 优化首尾项的竖线显示 */
.list-group-item-with-line:first-child::before {
  top: 50%;
}
.list-group-item-with-line:last-child::before {
  bottom: 50%;
}
</style>

<div class="bd-example">
  <div class="card" style="width: 18rem;">
    <img class="card-img-top" data-src="holder.js/100px180/?text=Image cap" alt="Image cap" style="height: 180px; width: 100%; display: block;" src="data:image/svg+xml;charset=UTF-8,%3Csvg%20width%3D%22286%22%20height%3D%22180%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20286%20180%22%20preserveAspectRatio%3D%22none%22%3E%3Cdefs%3E%3Cstyle%20type%3D%22text%2Fcss%22%3E%23holder_1879f97305a%20text%20%7B%20fill%3Argba(255%2C255%2C255%2C.75)%3Bfont-weight%3Anormal%3Bfont-family%3AHelvetica%2C%20monospace%3Bfont-size%3A14pt%20%7D%20%3C%2Fstyle%3E%3C%2Fdefs%3E%3Cg%20id%3D%22holder_1879f97305a%22%3E%3Crect%20width%3D%22286%22%20height%3D%22180%22%20fill%3D%22%23777%22%3E%3C%2Frect%3E%3Cg%3E%3Ctext%20x%3D%2299.12312316894531%22%20y%3D%2296.6%22%3EImage%20cap%3C%2Ftext%3E%3C%2Fg%3E%3C%2Fg%3E%3C%2Fsvg%3E"
      data-holder-rendered="true">
      
    <div class="card-body">
      <h5 class="card-title card-title-divider">Card title</h5>
    </div>
    
    <ul class="list-group list-group-flush">
      <li class="list-group-item list-group-item-with-line">Cras justo odio</li>
      <li class="list-group-item list-group-item-with-line">Dapibus ac facilisis in</li>
      <li class="list-group-item list-group-item-with-line">Vestibulum at eros</li>
    </ul>
    <div class="card-body"></div>
  </div>
</div>

方式二：用自定义div实现复杂连线 #

如果需要斜线、跨元素的复杂连线，可通过绝对定位的div实现，结合Bootstrap的position-relative类控制父容器定位：

示例代码（跨元素连线） #

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.2.3/dist/css/bootstrap.min.css" integrity="sha384-rbsA2VBKQhggwzxH7pPCaAqO46MgnOM80zW1RWuH61DGLwZJEdK2Kadq2F9CUG65" crossorigin="anonymous">

<style>
/* 父容器设置相对定位，作为连接线的定位基准 */
.connection-wrapper {
  position: relative;
  padding: 2rem;
}
/* 通用连接线样式 */
.custom-connector {
  position: absolute;
  background-color: var(--bs-danger); /* 使用Bootstrap危险色调 */
  z-index: 1;
}
/* 水平段连接线 */
.connector-horizontal {
  width: 60px;
  height: 2px;
  top: 32%;
  left: 0;
}
/* 垂直段连接线 */
.connector-vertical {
  width: 2px;
  height: 90px;
  top: 32%;
  left: 60px;
}
</style>

<div class="bd-example connection-wrapper">
  <!-- 左侧关联元素 -->
  <span class="badge bg-primary" style="position: absolute; top: 32%; left: -1.25rem;">关联标签</span>
  <!-- 自定义连接线 -->
  <div class="custom-connector connector-horizontal"></div>
  <div class="custom-connector connector-vertical"></div>
  
  <div class="card" style="width: 18rem; margin-left: 5rem;">
    <img class="card-img-top" data-src="holder.js/100px180/?text=Image cap" alt="Image cap" style="height: 180px; width: 100%; display: block;" src="data:image/svg+xml;charset=UTF-8,%3Csvg%20width%3D%22286%22%20height%3D%22180%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20286%20180%22%20preserveAspectRatio%3D%22none%22%3E%3Cdefs%3E%3Cstyle%20type%3D%22text%2Fcss%22%3E%23holder_1879f97305a%20text%20%7B%20fill%3Argba(255%2C255%2C255%2C.75)%3Bfont-weight%3Anormal%3Bfont-family%3AHelvetica%2C%20monospace%3Bfont-size%3A14pt%20%7D%20%3C%2Fstyle%3E%3C%2Fdefs%3E%3Cg%20id%3D%22holder_1879f97305a%22%3E%3Crect%20width%3D%22286%22%20height%3D%22180%22%20fill%3D%22%23777%22%3E%3C%2Frect%3E%3Cg%3E%3Ctext%20x%3D%2299.12312316894531%22%20y%3D%2296.6%22%3EImage%20cap%3C%2Ftext%3E%3C%2Fg%3E%3C%2Fg%3E%3C%2Fsvg%3E"
      data-holder-rendered="true">
      
    <div class="card-body">
      <h5 class="card-title">Card title</h5>
    </div>
    
    <ul class="list-group list-group-flush">
      <li class="list-group-item">Cras justo odio</li>
      <li class="list-group-item">Dapibus ac facilisis in</li>
      <li class="list-group-item">Vestibulum at eros</li>
    </ul>
    <div class="card-body"></div>
  </div>
</div>

关键提示 #

• 伪元素方式适合基础连线，不增加HTML结构冗余
• 自定义div方式支持任意形状的连线，通过调整width、height、top、left等属性可精准控制位置
• 优先使用Bootstrap内置颜色变量（如var(--bs-primary)），保证页面风格统一

内容的提问来源于stack exchange，提问作者parmijo Armijo