简单教程
提交运行
代码编辑器：
<!DOCTYPE htm> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"> <script src="https://cdn.bootcss.com/jquery/1.12.4/jquery.js"></script> <script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js"></script> <style>body {margin:20px}</style> <div class="alert alert-warning"> <a href="#" class="close" data-dismiss="alert"> × </a> <strong>警告！</strong>您的网络连接有问题 </div>
运行结果：