FAQ: calculate number of days between two dates in javascript

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FAQ: calculate number of days between two dates in javascript

October 24th, 2008 | Posted by Vijay Joshi | 11 Comments

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From today onwards I am introducing a new category FAQ. It will contain quick solutions and code for common problems developers face daily in javascript and php. Browser compatibility issues specially (Firefox and IE) will also be taken care of.
So here is the first one.

Q) How can I get the difference(number of days) between two dates in javascript?

A) Date and time operations in javascript can be done through the Date object. Default constructor for Date doesn’t take any argument and returns current date.

var aDate = new Date(); // will give current date

To get a specific date, you can provide year, month and day.

var anotherDate = new Date(yyyy,mm,dd);

Take care of the fact that months are from 0-11 i.e. January is 0 and December 11.
Hence, new Date(2008,10,09) is 9th November 2008 not 9th October.
Since there is not any inbuilt function for calculating date difference in javascript, we will use getTime() function. getTime() returns number of milliseconds since midnight of January 1, 1970.
Below is the code

var oneDay = 24*60*60*1000;	// hours*minutes*seconds*milliseconds
var firstDate = new Date(2008,01,12);
var secondDate = new Date(2008,01,22);

var diffDays = Math.abs((firstDate.getTime() - secondDate.getTime())/(oneDay));

What we did is

we took two dates
got milliseconds for each using getTime() function
calculated their difference
and finally divided the difference with the number of milliseconds in one day

Simple, isn’t it???

Posted in : FAQ, Javascript, Technology
Tags: FAQ, Javascript

10 Comments to “FAQ: calculate number of days between two dates in javascript”

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SathiyaCG says:

February 13, 2009 at 12:49 am

Thanks… Itz was very usefull

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Vijay says:

February 13, 2009 at 11:08 am

@SathiyaCG hey thanks!!!

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Satish Puli says:

March 10, 2009 at 10:40 am

Thanks it was very usefull
Thanks again.

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jose says:

May 28, 2009 at 3:44 pm

thank you, but what if I am not from USA and the date is in this format (dd,mm,yyyy)?

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jose says:

May 28, 2009 at 6:44 pm

Ok ,so I split the date into 3 array elements, then i put it in a variable like this var date=new Date(arr[2], arr[1], arr[0]) and thats it.Great, thanx.I did the same thing like this: date=new Date(date.split(‘/’).reverse().join(‘,’));

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jose says:

June 4, 2009 at 2:48 pm

I found out that the method: date=new Date(date.split(’/’).reverse().join(’,’)) only works in firefox not ie, because firefox accepts also strings in the date object, but ie doesn’t.So your method is the best method so far.
var dates=firstDate.split(‘/’);
var day = dates[0];
var month = dates[1]-1;
var year = dates[2];
firstDate = new Date(year, month, day);
This way the date object has inside paramaters not string

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Vijay says:

June 5, 2009 at 9:47 am

Cheers!!!

Reply
NDK says:

June 19, 2009 at 2:27 pm

If i try to do this it don’t work…

For example:
Current date is 2009,6,19
Test date is 2009,6,21

var date1=new Date(currentDate[2],(currentDate[1]-1),currentDate[0]);
var date2=new Date(datetest[2],(datetest[1]-1),datetest[0])
//I do -1 because: January is 0 and December 11

Current date: 2009,6,19
date: 2009,7,22
date2 = -1325638800000
date1 = -1420333200000
Dif: 1096
(= Math.abs((date1.getTime()-date2.getTime())/(one_day))

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brusky says:

July 3, 2009 at 1:51 pm

hi friends,
I need a function in javascript which must put live date into selectbox but user must select only 9 month higher not more so I will use it for pregnancy advise ,date must be max higher then user enter always will show 9 month
thnks I need your helps…

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Dipanjan Das says:

July 1, 2010 at 9:53 am

what is the difference between the dates : 11JUN10 and 11JUN12 ?

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