Javascript to calculate whether given date is current date or future date?

Question

In a date picker I want to restrict input to prevent dates in the past. I used the JavaScript below but it's failing in certain conditions.

 function isPastDate(value) {
        var now = new Date;
        var target = new Date(value);

        if (target.getFullYear() < now.getFullYear()) {
            return true;
        } else if (target.getMonth() < now.getMonth()) {
            return true;
        } else if (target.getDate() < now.getDate()) {
            return true;
        }
    return false;
}

Can someone help me?

You are over complicating a simple thing `console.log(now > target)` — epascarello, Feb 19 '14 at 15:01
Someone copied the answer from here: http://stackoverflow.com/questions/17344318/javascript-to-allow-only-current-and-future-dates ?? — epascarello, Feb 19 '14 at 15:03
@epascarello :if user gave 03/13/2014 it compare with current date. when comparing date it gets failed hence 13 less then 18. — Ryder, Feb 19 '14 at 15:13
@MarkWalters if user gave 03/13/2014 it compare with current date. when comparing date it gets failed hence 13 less then 18. — Ryder, Feb 19 '14 at 18:43

score 4 · Accepted Answer · answered Feb 19 '14 at 15:02

4

As epascarello stated, simply compare both dates:

function isPastDate(value) {
    return new Date() > new Date(value);
}

This happens because the date is measured in milliseconds since Jan 1st 1970 (correct me if I'm wrong), so what is really happening is a comparison between two long numbers.

answered Feb 19 '14 at 15:02

Danilo Valente

11,270
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If you want to use this at a later time you could use a time stamp. If not, this method works fine. See [this post](http://stackoverflow.com/questions/11893083/convert-normal-date-to-unix-timestamp) for JavaScript time stamps. – Marvin Brouwer Feb 19 '14 at 15:04

score 1 · Answer 2 · edited May 23 '17 at 12:03

1

See this post:

var selectedDate = $('#datepicker').datepicker('getDate');
var now = new Date();
if (selectedDate < now) {
  // selected date is in the past
}

edited May 23 '17 at 12:03

Community

1
1

answered Feb 19 '14 at 15:02

danielmhanover

3,094
4
35
51

score -1 · Answer 3 · answered Feb 19 '14 at 15:29

Your function is logically wrong, and doesn't check after if the years are actually the same before testing the months, same goes to months and days. You can try:

   function isPastDate(value) {
    var now = new Date;
    var target = new Date(value);

    if (target.getFullYear() < now.getFullYear()) {
        return true;
    } else if (target.getFullYear() === now.getFullYear())
        if (target.getMonth() < now.getMonth()) {
            return true;
        } else if (target.getMonth() === now.getMonth()) {
            if (target.getDate() < now.getDate()) {
                return true;
            }
        }
    }

    return false;
}

Hope that helps

Javascript to calculate whether given date is current date or future date?

3 Answers3