How to add some number of months to a given date using javascript

Question

I am trying to add months to a given date and want to output that date.

I am using this code, but it is not working.

    var p = '2015-10-21';
    var myDate = new Date(p);
    var result1 = myDate.addMonths(3);

I want the result to be: 2016-01-21

Date object doesn't have a method called addMonths – Jaromanda X Jan 09 '16 at 05:56 — Jaromanda X, Jan 09 '16 at 05:56
Please check your browser console for error debug – AddWeb Solution Pvt Ltd Jan 09 '16 at 05:57 — AddWeb Solution Pvt Ltd, Jan 09 '16 at 05:57
`.addMonths()` is in the datejs library... – John Hascall Jan 09 '16 at 06:04 — John Hascall, Jan 09 '16 at 06:04

Jaromanda X · Answer 1 · 2016-01-09T06:12:44.663

1

You want to getMonth/setMonth

var p = '2015-10-21';
var myDate = new Date(p);
myDate.setMonth(myDate.getMonth() + 3);

Don't worry about overflow - Date object handles it

Note. This overwrites myDate, if you want the result in a different var

var p = '2015-10-21';
var myDate = new Date(p);
var result1 = new Date(myDate);
result1.setMonth(result1.getMonth() + 3);

as noted by @JohnHascall in the comments, this isn't fool proof around the end of month, for example adding three months to 30 November 2015 will result in 1st March 2016

edited Jan 09 '16 at 06:12

answered Jan 09 '16 at 05:57

Jaromanda X

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Be careful around the end of months. For example: adding 3 months to the last day of November gives March 1st -- which may or may not be what you are expecting. – John Hascall Jan 09 '16 at 06:09
@JohnHascall Good point - I'll add that warning to the answer for completeness - does any library handle such cases, and what SHOULD be the result in such cases (guess that's a matter of opinion) – Jaromanda X Jan 09 '16 at 06:11
I think most date libraries would adjust that to the last day of the month. But as you say, what is 'right' is a matter of opinion. – John Hascall Jan 09 '16 at 06:15

sundar · Accepted Answer · 2016-01-09T06:28:16.627

The moment library is awesome for date related functions. You can do operations like add, subtract, etc. It has a syntax which is easily understandable.u can also avoid edge cases

If you included the moment library, your code could be rewritten like this

var p = '2015-10-21';
var myDate = moment(p, 'YYYY-MM-DD');
var result1 = myDate.add(3, 'months');
console.log (result1.format('YYYY-MM-DD'));

You can learn about or download moment from: http://momentjs.com/

score 0 · Answer 3 · answered Jan 09 '16 at 06:12

You can try this -

<script>
   var date = new Date();
   var month = date.getMonth()+1;
   var year = date.getFullYear();
   var day = date.getDate();

   function addMonth(addMonth){
     var u_date,u_year,u_month;
     u_date = month + addMonth;
     if(u_date > 12){
       var div = Math.floor(u_date / 12);
       var rem = u_date % 12;
       u_year = year + div;
       u_month = month + rem;
       document.getElementById("updated_date").innerHTML = day +" "+  u_month + " " + u_year;
     }else{
        document.getElementById("updated_date").innerHTML = day +" "+ (month+addMonth) + " " + year;
  }
}

addMonth(13);


</script>

Here is the html-

<div id="updated_date"></div>

How to add some number of months to a given date using javascript

3 Answers3