延伸链接

为链接添加 .stretched-link 类以使 包含该链接的块级元素 通过 ::after 伪元素变成可点击的区域。在大多数情况下，这意味着如果某个设置了 position: relative; 属性的元素包含一个带有 .stretched-link 类的链接的话，改元素将变成可点击的区域。请注意，鉴于 CSS position 的工作原理，.stretched-link 类不能与大多数表格元素混合使用。

Bootsrap 中的卡片（card）组件默认被设置了 position: relative 属性，因此在这种情况下，你可以安全地向卡片（card）组件中所包含的链接添加 .stretched-link 类，并且无需修改 HTML 代码。

延伸链接（stretched link）不支持多个链接和点击目标。但是，如果需要的话，你可以通过添加一些 position 和 z-index 样式来实现。

<div class="card" style="width: 18rem;">
  <img src="..." class="card-img-top" alt="...">
  <div class="card-body">
    <h5 class="card-title">Card with stretched link</h5>
    <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
    <a href="#" class="btn btn-primary stretched-link">Go somewhere</a>
  </div>
</div>

大部分自定义组件默认情况下都没有设置 position: relative 属性，因此需要需要自己添加 .position-relative 类，以防止链接溢出到父元素外。

<div class="d-flex position-relative">
  <img src="..." class="flex-shrink-0 me-3" alt="...">
  <div>
    <h5 class="mt-0">Custom component with stretched link</h5>
    <p>This is some placeholder content for the custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.</p>
    <a href="#" class="stretched-link">Go somewhere</a>
  </div>
</div>

<div class="row g-0 bg-light position-relative">
  <div class="col-md-6 mb-md-0 p-md-4">
    <img src="..." class="w-100" alt="...">
  </div>
  <div class="col-md-6 p-4 ps-md-0">
    <h5 class="mt-0">Columns with stretched link</h5>
    <p>Another instance of placeholder content for this other custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.</p>
    <a href="#" class="stretched-link">Go somewhere</a>
  </div>
</div>

识别包含块

如果延伸链接（stretched link）不起作用，则可能是 包含该链接的块级元素 导致的。以下 CSS 属性可以让包含延伸链接（stretched link）的元素变为块级元素：

• 为 position 设置 static 以外的值
• 为 transform 或 perspective 设置 none 以外的值
• 为 will-change 设置为 transform 或 perspective
• 为 filter 设置 none 以外的值，或者为 will-change 设置为 filter （仅适用于 Firefox 浏览器）

<div class="card" style="width: 18rem;">
  <img src="..." class="card-img-top" alt="...">
  <div class="card-body">
    <h5 class="card-title">Card with stretched links</h5>
    <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
    <p class="card-text">
      <a href="#" class="stretched-link text-danger" style="position: relative;">Stretched link will not work here, because <code>position: relative</code> is added to the link</a>
    </p>
    <p class="card-text bg-light" style="transform: rotate(0);">
      This <a href="#" class="text-warning stretched-link">stretched link</a> will only be spread over the <code>p</code>-tag, because a transform is applied to it.
    </p>
  </div>
</div>