var year = prompt("请输入年份");
if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
alert("是闰年")
} else {
alert("是平年")
}
var year = prompt("请输入年份");
if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
alert("是闰年")
} else {
alert("是平年")
}