Calculate javascript date

Question

i have the date 2013-12-28 and i want add one or more more day to it. so if i add one more day it will be 2013-12-29.
i try to add it by adding the value of it's date (date 28+1), it works, but what if i add 7 more day to it? the date will be 35, and of course it is not a valid date format.
can someone help me?
here's the example of my script:

var d = new Date();
var Y = d.getFullYear();
var M = d.getMonth()+1;
var D = d.getDate();
var DT = d.getDate()+1;// what if i + 20 days from today? the format would be invalid

var today = Y+"-"+M+"-"+D;
var tomorrow = Y+"-"+M+"-"+DT;
alert(today+" <> "+tomorrow);
// "<>" means nothing

Rahul Tripathi · Answer 1 · 2013-12-21T05:12:00.830

5

You may try like this using getdate(), setdate() and getdate():

var myDate = new Date();
myDate.setDate(myDate.getDate() + 7);

edited Dec 21 '13 at 05:12

answered Dec 21 '13 at 05:06

Rahul Tripathi

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yes,, setDate(). it helps – Oki Erie Rinaldi Dec 21 '13 at 05:25
@OkiErieRinaldi:- Yes it does the trick for you! :) – Rahul Tripathi Dec 21 '13 at 05:27

score 3 · Accepted Answer · answered Dec 21 '13 at 05:05

3

If you already have a date object as in the code you show:

 var d = new Date();

...then you can add 7 days to it like this:

d.setDate( d.getDate() + 7 );

...and it will automatically increment the month if needed.

Further reading:

If you need to extract the year, month and day in order to format the result a particular way do so after adding days.

answered Dec 21 '13 at 05:05

nnnnnn

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+1, never knew setDate will do auto increment – TwilightSun Dec 21 '13 at 05:18
aha, setDate(). it helps :D – Oki Erie Rinaldi Dec 21 '13 at 05:25

score 0 · Answer 3 · answered Dec 21 '13 at 05:13

The solution is to convert your date string into unix timestamp, and them add 3600 * 24 * <number of days> to the timestamp and them convert it back to date string.

The code can be as follows:

function addDaysToDate(date, days) {
    var time = Date.parse(date) + days * 24 * 3600;
    date = new Date(time);
    return date.getFullYear() + '-' + date.getMonth() + '-' + date.getDate();
}
var date = '2013-12-28';
console.log(addDaysToDate(date, 7));

Calculate javascript date

3 Answers3