<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
</body>
<script type="text/javascript">
var year=prompt("请输入年份");//弹出输入框
var a1=year%4==0;
var a2=year%100!=0;
var a3=year%400==0;
var result=(a1&&a2)||a3?"该年是闰年":"该年的平年";//三目运算符
alert(result);
</script>
</html>