说明

为警告框添加一个可选的 .alert-dismissible 类和一个关闭按钮

示例

<!DOCTYPE html>
<html lang="zh-CN">
  	<head>
    	<meta charset="utf-8">
    	<meta http-equiv="X-UA-Compatible" content="IE=edge">
    	<meta name="viewport" content="width=device-width, initial-scale=1">
    	<!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    	<title>Bootstrap 101 Template</title>

    	<!-- Bootstrap -->
    	<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

    	<!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
    	<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
    	<!--[if lt IE 9]>
      		<script src="https://cdn.bootcss.com/html5shiv/3.7.3/html5shiv.min.js"></script>
      		<script src="https://cdn.bootcss.com/respond.js/1.4.2/respond.min.js"></script>
    	<![endif]-->
  	</head>
  	<body>
  		<div class="container">
  			<div class="alert alert-success alert-dismissible" role="alert">
  				<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>
  				<strong>Well done!</strong> You successfully read this important alert message.
			</div>

			<div class="alert alert-info alert-dismissible" role="alert">
  				<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>
  				<strong>Heads up!</strong> This alert needs your attention, but it's not super important.
			</div>

  			<div class="alert alert-warning alert-dismissible" role="alert">
  				<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>
  				<strong>Warning!</strong> Better check yourself, you're not looking too good.
			</div>

			<div class="alert alert-danger alert-dismissible" role="alert">
  				<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>
  				<strong>Oh snap!</strong> Change a few things up and try submitting again.
			</div>
		</div>

    	<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
    	<script src="https://cdn.bootcss.com/jquery/1.12.4/jquery.min.js"></script>
    	<!-- Include all compiled plugins (below), or include individual files as needed -->
    	<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
  	</body>
</html>

输出

bootstrap-可关闭的警告框_bootstrap-可关闭的警告框