data-dismiss="alert"——为关闭button加入该属性能够使其自己主动为警告框赋予关闭功能。
.fade .in——为警告框在关闭时加入动画效果。
很多其它细节參考演示样例：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>js插件_警告框</title>
<link rel="stylesheet" href="bootstrap.min.css" type="text/css">
<!--<link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.5/css/bootstrap.min.css">-->
<script src="jquery-1.11.1.min.js"></script>
<script src="bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h3>警告框演示样例</h3>
<div class="alert alert-info alert-dismissible fade in" role="alert" id="myAlert">
<button type="button" class="close" data-dismiss="alert" aria-label="close">
<span aria-disabled="true">×</span>
</button>
感谢您选择<strong><要投哪></strong>
<button type="button" class="btn btn-primary">详情</button>
</div>
</div>
<script>
// $("#myAlert").alert('close');
// $('#myAlert').on('closed.bs.alert',function(e){
// alert("关闭了");
// })
</script>
</body>
</html>