运行截图如下：
代码如下；
- <!DOCTYPE html>
- <html lang="en">
- <head>
- <meta charset="UTF-8">
- <title>CN_TEST1</title>
- <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
-
- <!-- bootstrap css核心文件-->
- <link rel="stylesheet" href="bootstrap-4.4.1-dist/css/bootstrap.min.css">
- <!-- bootstrap使用到了jquery，需要提前引用-->
- <script src="js/jquery-3.5.1.min.js"></script>
- <!-- 弹窗、提示、下拉菜单-->
- <script src="bootstrap-4.4.1-dist/js/bootstrap.bundle.js"></script>
- <!-- bootstrap核心文件-->
- <script src="bootstrap-4.4.1-dist/js/bootstrap.min.js"></script>
-
- </head>
- <body>
-
- <div class="container-fluid">
-
- <div class="dropdown">
- <button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
- DropDown
- </button>
- <div class="dropdown-menu">
- <a class="dropdown-item" href="#">Link 1</a>
- <a class="dropdown-item" href="#">Link 2</a>
- <a class="dropdown-item" href="#">Link 3</a>
- </div>
- </div>
-
- <br/>
-
- <div class="dropdown">
-
- <a class="btn btn-secondary dropdown-toggle" href="#" role="button" id="dropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
- Dropdown
- </a>
-
- <div class="dropdown-menu" aria-labelledby="dropdownMenuLink">
- <div class="dropdown-header">Dropdown header 1</div>
- <a class="dropdown-item" href="#">Link 1</a>
- <a class="dropdown-item" href="#">Link 2</a>
- <div class="dropdown-divider"></div>
- <a class="dropdown-item disabled" href="#">Link 3</a>
- </div>
- </div>
-
- <br/>
-
-
-
- </div>
-
- </body>
- </html>
解释：
①实现下拉菜单的逻辑先在div中设置dropdown-menu，再到里面一层放dropdown-item；
