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"> <h2>Code</h2> <p>For multiple lines of code, use the pre element:</p> <pre>Text in a pre element is displayed in a fixed-width font, and it preserves both spaces and line breaks.</pre> <p>If you add the .pre-scrollable class, the pre element gets a max-height of 350px and provides a y-axis scrollbar:</p> <pre class="pre-scrollable">Text in a pre element is displayed in a fixed-width font, and it preserves both spaces and line breaks.</pre> </div> </body> </html>
运行结果