<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
var year = prompt("请输入年份");
// 闰年：能被4整除且不能被100整除 或 能被400整除
if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
alert("闰年");
} else {
alert("平年");
}
</script>
</body>
</html>