setDate with getDate + n returns today's date + n
Question
I want d2 to be d1 + 14 days, instead it's todays' date + 14 days.
<script type="text/javascript">
var d1 = new Date(2014, 7, 1);
var d2 = new Date();
d2.setDate(d1.getDate() + 14);
// d1 = Fri Aug 01 2014 00:00:00 GMT+0100 (GMT Daylight Time)
document.write("d1 = " + d1);
document.write("<br></br>")
// today's date is 16-04-2014
// d2 = Tue Apr 15 2014 17:36:03 GMT+0100 (GMT Daylight Time)
document.write("d2 = " + d2);
</script>
How can I make d2 = d1 + 14 days?
4 answers
solution1
5 ACCPTED 2014-04-16 16:52:43
setDate , somewhat surprisingly, sets the day-of-the-month of the existing instance. Since you've initialized d2 with today, you're just changing the day-of-month for that date, not taking on any other aspect of d1 .
You probably want:
var d1 = new Date(2014, 7, 1); // A specific date
var d2 = new Date(d1); // Clone that date
d2.setDate(d1.getDate() + 14); // Move forward 14 days
That gives us August 1st for d1 , and August 15th for d2 .
Another option is:
var d1 = new Date(2014, 7, 1);
var d2 = new Date(d1.getFullYear(), d1.getMonth(), d1.getDate() + 14);
Both of those work even when you're going past the end of the month, btw.
Complete example of the second option: Live Copy
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Date plus 14 days</title>
<style>
body {
font-family: sans-serif;
}
</style>
</head>
<body>
<script>
(function() {
var d1, d2;
display("Starting with August 1st:")
d1 = new Date(2014, 7, 1);
d2 = new Date(d1.getFullYear(), d1.getMonth(), d1.getDate() + 14);
display("d1 = " + d1);
display("d1 = " + d2);
document.body.appendChild(document.createElement('hr'));
display("Starting with August 20th:")
d1 = new Date(2014, 7, 20);
d2 = new Date(d1.getFullYear(), d1.getMonth(), d1.getDate() + 14);
display("d1 = " + d1);
display("d1 = " + d2);
function display(msg) {
var p = document.createElement('p');
p.innerHTML = String(msg);
document.body.appendChild(p);
}
})();
</script>
</body>
</html>
solution2
1 2014-04-16 16:52:35
You're making a new Date (today) for d2 but only changing the day, this should work:
var d1 = new Date(2014, 7, 1);
var d2 = new Date(2014, 7, d1.getDate()+14);
solution3
1 2014-04-16 16:56:45
Only put getTime() function inside d2 Date() function,
Check this Demo jsFiddle
JavaScript
var d1 = new Date(2014, 7, 1);
var d2 = new Date(d1.getTime());
d2.setDate(d1.getDate() + 14);
// d1 = Fri Aug 01 2014 00:00:00 GMT+0100 (GMT Daylight Time)
document.write("d1 = " + d1);
document.write("<br></br>")
// today's date is 16-04-2014
// d2 = Tue Apr 15 2014 17:36:03 GMT+0100 (GMT Daylight Time)
document.write("d2 = " + d2);
Result
d1 = Fri Aug 1 00:00:00 UTC+0530 2014
d2 = Fri Aug 15 00:00:00 UTC+0530 2014
solution4
1 2014-04-16 16:59:28
d1 is a date in August, d2 is today. You are setting d2 to today + 14 days. The proper result is below:
var d1 = new Date(2014, 7, 1);
var d2 = new Date(d1.setDate(d1.getDate() + 12));
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.