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> <style> body { position: relative; } </style> </head> <body data-spy="scroll" data-target=".navbar" data-offset="50"> <nav class="navbar navbar-expand-sm bg-dark navbar-dark fixed-top"> <ul class="navbar-nav"> <li class="nav-item"> <a class="nav-link" href="#section1">Section 1</a> </li> <li class="nav-item"> <a class="nav-link" href="#section2">Section 2</a> </li> <li class="nav-item"> <a class="nav-link" href="#section3">Section 3</a> </li> <li class="nav-item dropdown"> <a class="nav-link dropdown-toggle" href="#" id="navbardrop" data-toggle="dropdown"> Section 4 </a> <div class="dropdown-menu"> <a class="dropdown-item" href="#section41">Link 1</a> <a class="dropdown-item" href="#section42">Link 2</a> </div> </li> </ul> </nav> <div id="section1" class="container-fluid bg-success" style="padding-top:70px;padding-bottom:70px"> <h1>Section 1</h1> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> </div> <div id="section2" class="container-fluid bg-warning" style="padding-top:70px;padding-bottom:70px"> <h1>Section 2</h1> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> </div> <div id="section3" class="container-fluid bg-secondary" style="padding-top:70px;padding-bottom:70px"> <h1>Section 3</h1> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> </div> <div id="section41" class="container-fluid bg-danger" style="padding-top:70px;padding-bottom:70px"> <h1>Section 4 Submenu 1</h1> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> </div> <div id="section42" class="container-fluid bg-info" style="padding-top:70px;padding-bottom:70px"> <h1>Section 4 Submenu 2</h1> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> <p>Try to scroll this section and look at the navigation bar while scrolling! Try to scroll this section and look at the navigation bar while scrolling!</p> </div> </body> </html>
运行结果