<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<script>
function fun(){
var year = document.getElementById('year').value;
var month = document.getElementById('month').value;
var day = document.getElementById('day').value;
var sum_day;//總天數
sum_day = new Date(month + '-' + day + '-' + year);
now_year = new Date().getFullYear();
one = new Date(1 + '-' + 1 + '-' + year);
parseInt(Math.abs(sum_day - one) / 1000 / 60 / 60 /24);
alert(parseInt(Math.abs(sum_day - one) / 1000 / 60 / 60 /24)+1);
}
</script>
</head>
<body>
年: <input type="number" id="year"/><br/>
月: <input type="number" id="month"/><br/>
日: <input type="number" id="day"/><br/>
<input type="button" id="" value="計算" οnclick="fun()"/><br/>
</body>
</html>
