模态框（Modal）是覆盖在父窗体上的子窗体。通常，目的是显示来自一个单独的源的内容，可以在不离开父窗体的情况下有一些互动。子窗体可提供信息交互等。
如何创建模态框 以下实例创建了一个简单的模态框效果 ： <!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.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css"> <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script> <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script> <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <h2>模态框实例</h2> <!-- 按钮：用于打开模态框 --> <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#myModal"> 打开模态框 </button> <!-- 模态框 --> <div class="modal fade" id="myModal"> <div class="modal-dialog"> <div class="modal-content"> <!-- 模态框头部 --> <div class="modal-header"> <h4 class="modal-title">模态框头部</h4> <button type="button" class="close" data-dismiss="modal">×</button> </div> <!-- 模态框主体 --> <div class="modal-body"> 模态框内容.. </div> <!-- 模态框底部 --> <div class="modal-footer"> <button type="button" class="btn btn-secondary" data-dismiss="modal">关闭</button> </div> </div> </div> </div> </div> </body> </html>
模态框尺寸 我们可以通过添加 .modal-sm 类来创建一个小模态框，.modal-lg 类可以创建一个大模态框。 尺寸类放在 <div>元素的 .modal-dialog 类后 : <!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.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css"> <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script> <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script> <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <h2>模态框实例</h2> <!-- 按钮：用于打开模态框 --> <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#myModal"> 打开模态框 </button> <!-- 模态框 --> <div class="modal fade" id="myModal"> <div class="modal-dialog modal-sm"> <div class="modal-content"> <!-- 模态框头部 --> <div class="modal-header"> <h4 class="modal-title">模态框头部</h4> <button type="button" class="close" data-dismiss="modal">×</button> </div> <!-- 模态框主体 --> <div class="modal-body"> 模态框内容.. </div> <!-- 模态框底部 --> <div class="modal-footer"> <button type="button" class="btn btn-secondary" data-dismiss="modal">关闭</button> </div> </div> </div> </div> </div> </body> </html>
实例 - 大模态框 <!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.bootcss.com/bootstrap/4.1.0/css/bootstrap.min.css"> <script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script> <script src="https://cdn.bootcss.com/popper.js/1.12.5/umd/popper.min.js"></script> <script src="https://cdn.bootcss.com/bootstrap/4.1.0/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <h2>模态框实例</h2> <!-- 按钮：用于打开模态框 --> <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#myModal"> 打开模态框 </button> <!-- 模态框 --> <div class="modal fade" id="myModal"> <div class="modal-dialog modal-lg"> <div class="modal-content"> <!-- 模态框头部 --> <div class="modal-header"> <h4 class="modal-title">模态框头部</h4> <button type="button" class="close" data-dismiss="modal">×</button> </div> <!-- 模态框主体 --> <div class="modal-body"> 模态框内容.. </div> <!-- 模态框底部 --> <div class="modal-footer"> <button type="button" class="btn btn-secondary" data-dismiss="modal">关闭</button> </div> </div> </div> </div> </div> </body> </html>