js判断年份
<html lang="en">
<head>
<meta charset="UTF-8">
<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");
if (year%4==0 && year%100!==0 ||year%400==0) {
alert("闰年");
}
else {
alert("平年");
}
</script>
</body>
</html>