<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<script type="text/javascript">
let year = prompt('请输入你的出生年份');
if(year%100 == 0){
if(year%400 == 0){
document.write(year+'年是闰年');
}
}
else if(year%4 == 0){
document.write(year+'年是闰年');
}
else{
document.write(year+'年不是闰年');
}
</script>
</body>
</html>