Determining Date Equality in Javascript

Question

I need to find out if two dates the user selects are the same in Javascript. The dates are passed to this function in a String ("xx/xx/xxxx").That is all the granularity I need.

Here is my code:

        var valid = true;
    var d1 = new Date($('#datein').val());
    var d2 = new Date($('#dateout').val());
    alert(d1+"\n"+d2);
    if(d1 > d2) {
        alert("Your check out date must be after your check in date.");
        valid = false;
    } else if(d1 == d2) {
        alert("You cannot check out on the same day you check in.");
        valid = false;
    }

The javascript alert after converting the dates to objects looks like this:

Tue Jan 25 2011 00:00:00 GMT-0800 (Pacific Standard Time)

The test to determine if date 1 is greater than date 2 works. But using the == or === operators do not change valid to false.

Have you checked this post out: stackoverflow.com/questions/338463/…. Does it help? — JohnMerlino
– JohnMerlino, Commented Jan 3, 2011 at 18:21
Tempted to flag this as a duplicate but I think this is a fringe case of the same issue, so I'm not. — Liam
– Liam, Commented Nov 20, 2013 at 10:52
This is not a duplicate. The post mentionned (and the accepted answer) are about determining if a date is before or after another, not about equality. — yannick1976
– yannick1976, Commented Jul 23, 2015 at 17:49

Andrew Rasmussen · Accepted Answer · 2018-04-22 07:20:46Z

186

Use the getTime() method. It will check the numeric value of the date and it will work for both the greater than/less than checks as well as the equals checks.

EDIT:

if (d1.getTime() === d2.getTime())

edited Apr 22, 2018 at 7:20

Andrew Rasmussen

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answered Jan 3, 2011 at 18:20

spinon

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2 Comments

JohnMerlino Over a year ago

And the stackoverflow question I posted above shows an example. The questions were identical.

GetFree Over a year ago

A simpler way: if( +d1 == +d2 )

devmiles.com · Accepted Answer · 2013-09-11 13:56:50Z

26

If you don't want to call getTime() just try this:

(a >= b && a <= b)

answered Sep 11, 2013 at 13:56

devmiles.com

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7 Comments

Kuepper Over a year ago

WTF? Why does that work but the equality operator does not? Where is the sense in that?

Tomas Over a year ago

The equality operator checks for reference equality. This means it only returns true if the two variables refer the the same object. If you create two Date objects (var a = new Date(); var b = new Date();), they will never be equal.

amd Over a year ago

@devmiles.com except for string, that are compared by value also, var a ="str1"; var b = "str"+"1"; a == b // true

JonnyRaa Over a year ago

wierd. You would have thought this would have actually been a place where a seperation between == and === would make sense... Oh wait its javascript. We dont do sense here!

Mike Schenk Over a year ago

@Towa, That works because the >= and <= operators only work on numbers, so they try to convert their operands to numbers. And to convert an object (such as a Date) to a number, JavaScript calls the valueOf() function to get a numeric representation. valueOf() returns the same thing as getTime(): developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…

|

Arjun Kubendran · Accepted Answer · 2017-03-21 19:57:57Z

4

var d1 = new Date($('#datein').val());
var d2 = new Date($('#dateout').val());

use two simple ways to check equality

if( d1.toString() === d2.toString())
if( +d1 === +d2)

answered Mar 21, 2017 at 19:57

Arjun Kubendran

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Comments

Liam Bohl · Accepted Answer · 2023-08-08 16:08:16Z

0

Instead of comparing the dates directly, you can check that their difference is zero.

if (d1 - d2 === 0)

answered Aug 8, 2023 at 16:08

Liam Bohl

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Comments

mousetail · Accepted Answer · 2023-10-09 11:27:05Z

-3

var date = "Wed Oct 07 2015 19:48:08 GMT+0200 (Central European Daylight Time)";

var dateOne = new Date(date);
var dateTwo = new Date();

var isEqual = dateOne.getDate() === dateTwo.getDate()

this will give you the dates equality

edited Oct 9, 2023 at 11:27

mousetail

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answered Feb 8, 2021 at 3:36

Jack Van

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2 Comments

costaparas Over a year ago

The community encourages adding explanations alongisde code, rather than purely code-based answers (see here).

Mark Fisher Over a year ago

This is wrong. The 7th April is not the same as the 7th March.

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