源代码 ：
点击运行
<!DOCTYPE html> <html> <head> <title>Bootstrap 实例</title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/css/bootstrap.min.css"> <script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script> <script src="https://cdn.staticfile.org/popper.js/1.15.0/umd/popper.min.js"></script> <script src="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/js/bootstrap.min.js"></script> </head> <body> <div class="container mt-3"> <h2>等宽</h2> <p>.flex-fill 类强制设置各个弹性子元素的宽度是一样的，.flex-*-fill 可以根据不同屏幕设备设置。</p> <p>重置浏览器窗口大小，查看效果。</p> <p><code>.flex-fill</code>:</p> <div class="d-flex mb-3 bg-secondary"> <div class="p-2 flex-fill bg-info">Flex item 1</div> <div class="p-2 flex-fill bg-warning">Flex item 2</div> <div class="p-2 flex-fill bg-primary">Flex item 3</div> </div> <p><code>.flex-sm-fill</code>:</p> <div class="d-flex mb-3 bg-secondary"> <div class="p-2 flex-sm-fill bg-info">Flex item 1</div> <div class="p-2 flex-sm-fill bg-warning">Flex item 2</div> <div class="p-2 flex-sm-fill bg-primary">Flex item 3</div> </div> <p><code>.flex-md-fill</code>:</p> <div class="d-flex mb-3 bg-secondary"> <div class="p-2 flex-md-fill bg-info">Flex item 1</div> <div class="p-2 flex-md-fill bg-warning">Flex item 2</div> <div class="p-2 flex-md-fill bg-primary">Flex item 3</div> </div> <p><code>.flex-lg-fill</code>:</p> <div class="d-flex mb-3 bg-secondary"> <div class="p-2 flex-lg-fill bg-info">Flex item 1</div> <div class="p-2 flex-lg-fill bg-warning">Flex item 2</div> <div class="p-2 flex-lg-fill bg-primary">Flex item 3</div> </div> <p><code>.flex-xl-fill</code>:</p> <div class="d-flex mb-3 bg-secondary"> <div class="p-2 flex-xl-fill bg-info">Flex item 1</div> <div class="p-2 flex-xl-fill bg-warning">Flex item 2</div> <div class="p-2 flex-xl-fill bg-primary">Flex item 3</div> </div> </div> </body> </html>
运行结果