Bootstrap4 模态框
模态框（Modal）是覆盖在父窗体上的子窗体。通常，使用模态框的目的是用来显示来自一个单独的源的内容，而且可以在不离开父窗体的情况下有一些互动。
模态框创建：
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap4 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>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。
尺寸类都放在 <div>元素的 .modal-dialog 类后 :
实例：实例 - 大模态框
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap4 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>Bootstrap4 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>