要在特定的屏幕宽度上创建块，请使用.d-*-block类。
特定的屏幕宽度可以是小，中，大和特大。根据屏幕尺寸分别设置类，如下所示-
<span class="d-sm-block bg-primary"> d-sm-block </span> <span class="d-md-block bg-success"> d-md-block </span> <span class="d-lg-block bg-info"> d-lg-block< /span> <span class="d-xl-block bg-warning"> d-xl-block </span>
让我们看完整的示例，以学习如何在特定的屏幕宽度上创建一个块元素-
<!DOCTYPE html> <html> <head> <title>Bootstrap Example</title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css"> <script src="https://cdn.staticfile.org/jquery/3.3.1/jquery.min.js"></script> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script> </head> <body> <div class="container mt-3"> <h2>Blocks</h2> <p>Resize the browser to check the effect</p> <span class="d-block bg-info">d-block</span> <span class="d-sm-block bg-primary">d-sm-block</span> <span class="d-md-block bg-success">d-md-block</span> <span class="d-lg-block bg-info">d-lg-block</span> <span class="d-xl-block bg-warning">d-xl-block</span> </div> </body> </html>