如下所示：
HTML
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<title>Layui</title>
<link rel="stylesheet" href="js/css/layui.css" rel="external nofollow" media="all">
</head>
<body>
<div class="layui-sid
