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Date

Creates a JavaScript Date instance that represents a single moment in time. Date objects are based on a time value that is the number of milliseconds since 1 January 1970 UTC.

Syntax

new Date();
new Date(value);
new Date(dateString);
new Date(year, monthIndex [, day [, hours [, minutes [, seconds [, milliseconds]]]]]);

Note: JavaScript Date objects can only be instantiated by calling JavaScript Date as a constructor: calling it as a regular function (i.e. without the new operator) will return a string rather than a Date object; unlike other JavaScript object types, JavaScript Date objects have no literal syntax.

Parameters

Note: The argument monthIndex is 0-based. This means that January = 0 and December = 11.

Note: Where Date is called as a constructor with more than one argument, if values are greater than their logical range (e.g. 13 is provided as the month value or 70 for the minute value), the adjacent value will be adjusted. E.g. new Date(2013, 13, 1) is equivalent to new Date(2014, 1, 1), both create a date for 2014-02-01 (note that the month is 0-based). Similarly for other values: new Date(2013, 2, 1, 0, 70) is equivalent to new Date(2013, 2, 1, 1, 10) which both create a date for 2013-03-01T01:10:00.

Note: Where Date is called as a constructor with more than one argument, the specified arguments represent local time. If UTC is desired, use new Date(Date.UTC(...)) with the same arguments.

value: Integer value representing the number of milliseconds since January 1, 1970, 00:00:00 UTC, with leap seconds ignored (Unix Epoch; but consider that most Unix timestamp functions count in seconds).
dateString: String value representing a date. The string should be in a format recognized by the Date.parse() method (IETF-compliant RFC 2822 timestamps and also a version of ISO8601).

Note: parsing of date strings with the Date constructor (and Date.parse, they are equivalent) is strongly discouraged due to browser differences and inconsistencies. Support for RFC 2822 format strings is by convention only. Support for ISO 8601 formats differs in that date-only strings (e.g. "1970-01-01") are treated as UTC, not local.
year: Integer value representing the year. Values from 0 to 99 map to the years 1900 to 1999. See the example below.
monthIndex: Integer value representing the month, beginning with 0 for January to 11 for December.
day Optional: Integer value representing the day of the month.
hours Optional: Integer value representing the hour of the day.
minutes Optional: Integer value representing the minute segment of a time.
seconds Optional: Integer value representing the second segment of a time.
milliseconds Optional: Integer value representing the millisecond segment of a time.

Description

If no arguments are provided, the constructor creates a JavaScript Date object for the current date and time according to system settings for timezone offset.
If at least two arguments are supplied, missing arguments are either set to 1 (if the day is missing) or 0 for all others.
The JavaScript date is based on a time value that is milliseconds since midnight January 1, 1970, UTC. A day holds 86,400,000 milliseconds. The JavaScript Date object range is -100,000,000 days to 100,000,000 days relative to January 1, 1970 UTC.
The JavaScript Date object provides uniform behavior across platforms. The time value can be passed between systems to create a date that represents the same moment in time.
The JavaScript Date object supports a number of UTC (universal) methods, as well as local time methods. UTC, also known as Greenwich Mean Time (GMT), refers to the time as set by the World Time Standard. The local time is the time known to the computer where JavaScript is executed.
Invoking JavaScript Date as a function (i.e., without the new operator) will return a string representing the current date and time.

Properties

Date.prototype: Allows the addition of properties to a JavaScript Date object.
Date.length: The value of Date.length is 7. This is the number of arguments handled by the constructor.

Methods

Date.now(): Returns the numeric value corresponding to the current time - the number of milliseconds elapsed since January 1, 1970 00:00:00 UTC, with leap seconds ignored.
Date.parse(): Parses a string representation of a date and returns the number of milliseconds since 1 January, 1970, 00:00:00, UTC, with leap seconds ignored.

Note: Parsing of strings with Date.parse is strongly discouraged due to browser differences and inconsistencies.
Date.UTC(): Accepts the same parameters as the longest form of the constructor (i.e. 2 to 7) and returns the number of milliseconds since January 1, 1970, 00:00:00 UTC, with leap seconds ignored.

JavaScript `Date` instances

All Date instances inherit from Date.prototype. The prototype object of the Date constructor can be modified to affect all Date instances.

Date.prototype Methods

Getter

Date.prototype.getDate(): Returns the day of the month (1-31) for the specified date according to local time.
Date.prototype.getDay(): Returns the day of the week (0-6) for the specified date according to local time.
Date.prototype.getFullYear(): Returns the year (4 digits for 4-digit years) of the specified date according to local time.
Date.prototype.getHours(): Returns the hour (0-23) in the specified date according to local time.
Date.prototype.getMilliseconds(): Returns the milliseconds (0-999) in the specified date according to local time.
Date.prototype.getMinutes(): Returns the minutes (0-59) in the specified date according to local time.
Date.prototype.getMonth(): Returns the month (0-11) in the specified date according to local time.
Date.prototype.getSeconds(): Returns the seconds (0-59) in the specified date according to local time.
Date.prototype.getTime(): Returns the numeric value of the specified date as the number of milliseconds since January 1, 1970, 00:00:00 UTC (negative for prior times).
Date.prototype.getTimezoneOffset(): Returns the time-zone offset in minutes for the current locale.
Date.prototype.getUTCDate(): Returns the day (date) of the month (1-31) in the specified date according to universal time.
Date.prototype.getUTCDay(): Returns the day of the week (0-6) in the specified date according to universal time.
Date.prototype.getUTCFullYear(): Returns the year (4 digits for 4-digit years) in the specified date according to universal time.
Date.prototype.getUTCHours(): Returns the hours (0-23) in the specified date according to universal time.
Date.prototype.getUTCMilliseconds(): Returns the milliseconds (0-999) in the specified date according to universal time.
Date.prototype.getUTCMinutes(): Returns the minutes (0-59) in the specified date according to universal time.
Date.prototype.getUTCMonth(): Returns the month (0-11) in the specified date according to universal time.
Date.prototype.getUTCSeconds(): Returns the seconds (0-59) in the specified date according to universal time.
Date.prototype.getYear(): Returns the year (usually 2-3 digits) in the specified date according to local time. Use getFullYear() instead.

Setter

Date.prototype.setDate(): Sets the day of the month for a specified date according to local time.
Date.prototype.setFullYear(): Sets the full year (e.g. 4 digits for 4-digit years) for a specified date according to local time.
Date.prototype.setHours(): Sets the hours for a specified date according to local time.
Date.prototype.setMilliseconds(): Sets the milliseconds for a specified date according to local time.
Date.prototype.setMinutes(): Sets the minutes for a specified date according to local time.
Date.prototype.setMonth(): Sets the month for a specified date according to local time.
Date.prototype.setSeconds(): Sets the seconds for a specified date according to local time.
Date.prototype.setTime(): Sets the Date object to the time represented by a number of milliseconds since January 1, 1970, 00:00:00 UTC, allowing for negative numbers for times prior.
Date.prototype.setUTCDate(): Sets the day of the month for a specified date according to universal time.
Date.prototype.setUTCFullYear(): Sets the full year (e.g. 4 digits for 4-digit years) for a specified date according to universal time.
Date.prototype.setUTCHours(): Sets the hour for a specified date according to universal time.
Date.prototype.setUTCMilliseconds(): Sets the milliseconds for a specified date according to universal time.
Date.prototype.setUTCMinutes(): Sets the minutes for a specified date according to universal time.
Date.prototype.setUTCMonth(): Sets the month for a specified date according to universal time.
Date.prototype.setUTCSeconds(): Sets the seconds for a specified date according to universal time.
Date.prototype.setYear(): Sets the year (usually 2-3 digits) for a specified date according to local time. Use setFullYear() instead.

Conversion getter

Date.prototype.toDateString(): Returns the "date" portion of the Date as a human-readable string like 'Thu Apr 12 2018'
Date.prototype.toISOString(): Converts a date to a string following the ISO 8601 Extended Format.
Date.prototype.toJSON(): Returns a string representing the Date using toISOString(). Intended for use by JSON.stringify().
Date.prototype.toGMTString(): Returns a string representing the Date based on the GMT (UT) time zone. Use toUTCString() instead.
Date.prototype.toLocaleDateString(): Returns a string with a locality sensitive representation of the date portion of this date based on system settings.
Date.prototype.toLocaleFormat(): Converts a date to a string, using a format string.
Date.prototype.toLocaleString(): Returns a string with a locality sensitive representation of this date. Overrides the Object.prototype.toLocaleString() method.
Date.prototype.toLocaleTimeString(): Returns a string with a locality sensitive representation of the time portion of this date based on system settings.
Date.prototype.toSource(): Returns a string representing the source for an equivalent Date object; you can use this value to create a new object. Overrides the Object.prototype.toSource() method.
Date.prototype.toString(): Returns a string representing the specified Date object. Overrides the Object.prototype.toString() method.
Date.prototype.toTimeString(): Returns the "time" portion of the Date as a human-readable string.
Date.prototype.toUTCString(): Converts a date to a string using the UTC timezone.
Date.prototype.valueOf(): Returns the primitive value of a Date object. Overrides the Object.prototype.valueOf() method.

Examples

Several ways to create a `Date` object

The following examples show several ways to create JavaScript dates:

Note: parsing of date strings with the Date constructor (and Date.parse, they are equivalent) is strongly discouraged due to browser differences and inconsistencies.

var today = new Date();
var birthday = new Date('December 17, 1995 03:24:00');
var birthday = new Date('1995-12-17T03:24:00');
var birthday = new Date(1995, 11, 17);
var birthday = new Date(1995, 11, 17, 3, 24, 0);

Two digit years map to 1900 - 1999

In order to create and get dates between the years 0 and 99 the Date.prototype.setFullYear() and Date.prototype.getFullYear() methods should be used.

var date = new Date(98, 1); // Sun Feb 01 1998 00:00:00 GMT+0000 (GMT)

// Deprecated method, 98 maps to 1998 here as well
date.setYear(98);           // Sun Feb 01 1998 00:00:00 GMT+0000 (GMT)

date.setFullYear(98);       // Sat Feb 01 0098 00:00:00 GMT+0000 (BST)

Calculating elapsed time

The following examples show how to determine the elapsed time between two JavaScript dates in milliseconds.

Due to the differing lengths of days (due to daylight saving changeover), months and years, expressing elapsed time in units greater than hours, minutes and seconds requires addressing a number of issues and should be thoroughly researched before being attempted.

// using Date objects
var start = Date.now();

// the event to time goes here:
doSomethingForALongTime();
var end = Date.now();
var elapsed = end - start; // elapsed time in milliseconds

// using built-in methods
var start = new Date();

// the event to time goes here:
doSomethingForALongTime();
var end = new Date();
var elapsed = end.getTime() - start.getTime(); // elapsed time in milliseconds

// to test a function and get back its return
function printElapsedTime(fTest) {
  var nStartTime = Date.now(),
      vReturn = fTest(),
      nEndTime = Date.now();

  console.log('Elapsed time: ' + String(nEndTime - nStartTime) + ' milliseconds');
  return vReturn;
}

var yourFunctionReturn = printElapsedTime(yourFunction);

Note: In browsers that support the Web Performance API's high-resolution time feature, Performance.now() can provide more reliable and precise measurements of elapsed time than Date.now().

Get the number of seconds since Unix Epoch

var seconds = Math.floor(Date.now() / 1000);

In this case it's important to return only an integer (so a simple division won't do), and also to only return actually elapsed seconds (that's why this code uses Math.floor() and not Math.round()).

Specifications

Specification	Status	Comment
ECMAScript Latest Draft (ECMA-262) The definition of 'Date' in that specification.	Draft
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Date' in that specification.	Standard
ECMAScript 5.1 (ECMA-262) The definition of 'Date' in that specification.	Standard
ECMAScript 1st Edition (ECMA-262)	Standard	Initial definition. Implemented in JavaScript 1.1.

Browser compatibilityUpdate compatibility data on GitHub

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	Yes	Yes	1	Yes Yes The ISO8601 Date Format is not supported in Internet Explorer 8.	Yes	Yes
`@@toPrimitive`	?	?	44	?	?	?
`UTC`	Yes	Yes	1	Yes	Yes	Yes
`getDate`	Yes	Yes	1	Yes	Yes	Yes
`getDay`	Yes	Yes	1	Yes	Yes	Yes
`getFullYear`	Yes	Yes	1	Yes	Yes	Yes
`getHours`	Yes	Yes	1	Yes	Yes	Yes
`getMilliseconds`	Yes	Yes	1	Yes	Yes	Yes
`getMinutes`	Yes	Yes	1	Yes	Yes	Yes
`getMonth`	Yes	Yes	1	Yes	Yes	Yes
`getSeconds`	Yes	Yes	1	Yes	Yes	Yes
`getTime`	Yes	Yes	1	Yes	Yes	Yes
`getTimezoneOffset`	Yes	Yes	1	5	Yes	Yes
`getUTCDate`	Yes	Yes	1	Yes	Yes	Yes
`getUTCDay`	Yes	Yes	1	Yes	Yes	Yes
`getUTCFullYear`	Yes	Yes	1	Yes	Yes	Yes
`getUTCHours`	Yes	Yes	1	Yes	Yes	Yes
`getUTCMilliseconds`	Yes	Yes	1	Yes	Yes	Yes
`getUTCMinutes`	Yes	Yes	1	Yes	Yes	Yes
`getUTCMonth`	Yes	Yes	1	Yes	Yes	Yes
`getUTCSeconds`	Yes	Yes	1	Yes	Yes	Yes
`getYear`	Yes	Yes	1	Yes	Yes	Yes
`now`	5	Yes	3	9	10.5	4
`parse`	Yes	Yes	1	Yes	Yes	Yes
`parse`: ISO 8601 format	Yes	?	4	9	Yes	Yes
`prototype`	Yes	Yes	1	Yes	Yes	Yes
`prototype`: Ordinary object (ES2015)	?	?	41	?	?	?
`setDate`	Yes	Yes	1	Yes	Yes	Yes
`setFullYear`	Yes	Yes	1	Yes	Yes	Yes
`setHours`	Yes	Yes	1	Yes	Yes	Yes
`setMilliseconds`	Yes	Yes	1	Yes	Yes	Yes
`setMinutes`	Yes	Yes	1	Yes	Yes	Yes
`setMonth`	Yes	Yes	1	Yes	Yes	Yes
`setSeconds`	Yes	Yes	1	Yes	Yes	Yes
`setTime`	Yes	Yes	1	Yes	Yes	Yes
`setUTCDate`	Yes	Yes	1	Yes	Yes	Yes
`setUTCFullYear`	Yes	Yes	1	Yes	Yes	Yes
`setUTCHours`	Yes	Yes	1	Yes	Yes	Yes
`setUTCMilliseconds`	Yes	Yes	1	Yes	Yes	Yes
`setUTCMinutes`	Yes	Yes	1	Yes	Yes	Yes
`setUTCMonth`	Yes	Yes	1	Yes	Yes	Yes
`setUTCSeconds`	Yes	Yes	1	Yes	Yes	Yes
`setYear`	Yes	Yes	1	Yes	Yes	Yes
`toDateString`	Yes	Yes	1	Yes	Yes	Yes
`toGMTString`	Yes	Yes	1	Yes	Yes	Yes
`toISOString`	Yes	Yes	1	9	Yes	Yes
`toJSON`	Yes	Yes	1	8	Yes	Yes
`toLocaleDateString`	Yes	Yes	1	Yes	Yes	Yes
`toLocaleDateString.locales`	24	Yes	29	11	15	10
`toLocaleDateString.options`	24	Yes	29	11	15	10
`toLocaleDateString`: IANA time zone names in `timeZone` option	24	?	52	?	?	?
`toLocaleFormat`	No	No	1.5 — 58	No	No	No
`toLocaleString`	Yes	Yes	1	Yes	Yes	Yes
`toLocaleString.locales`	24	?	29	11	15	10
`toLocaleString.options`	24	?	29	11	15	10
`toLocaleString`: IANA time zone names in `timeZone` option	24	?	52	?	?	?
`toLocaleTimeString`	Yes	Yes	1	Yes	Yes	Yes
`toLocaleTimeString.locales`	24	?	29	11	15	10
`toLocaleTimeString.options`	24	?	29	11	15	10
`toLocaleTimeString`: IANA time zone names in `timeZone` option	24	?	52	?	?	?
`toSource`	No	No	1	No	No	No
`toString`	Yes	Yes	1	Yes	Yes	Yes
`toTimeString`	Yes	Yes	1	Yes	Yes	Yes
`toUTCString`	Yes	Yes	1	Yes	Yes	Yes
`valueOf`	Yes	Yes	1	Yes	Yes	Yes

	Mobile
	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support	Yes	Yes	Yes	4	Yes	Yes	Yes
`@@toPrimitive`	?	?	?	44	?	?	?
`UTC`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getDate`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getDay`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getFullYear`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getHours`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getMilliseconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getMinutes`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getMonth`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getSeconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getTime`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getTimezoneOffset`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCDate`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCDay`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCFullYear`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCHours`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCMilliseconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCMinutes`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCMonth`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getUTCSeconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`getYear`	Yes	Yes	Yes	4	Yes	Yes	Yes
`now`	Yes	Yes	Yes	4	Yes	Yes	Yes
`parse`	Yes	Yes	Yes	4	Yes	Yes	Yes
`parse`: ISO 8601 format	Yes	Yes	?	4	Yes	Yes	Yes
`prototype`	Yes	Yes	Yes	4	Yes	Yes	Yes
`prototype`: Ordinary object (ES2015)	?	?	?	41	?	?	?
`setDate`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setFullYear`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setHours`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setMilliseconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setMinutes`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setMonth`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setSeconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setTime`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setUTCDate`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setUTCFullYear`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setUTCHours`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setUTCMilliseconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setUTCMinutes`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setUTCMonth`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setUTCSeconds`	Yes	Yes	Yes	4	Yes	Yes	Yes
`setYear`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toDateString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toGMTString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toISOString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toJSON`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toLocaleDateString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toLocaleDateString.locales`	No	26	?	56	No	10	Yes
`toLocaleDateString.options`	No	26	?	56	No	10	Yes
`toLocaleDateString`: IANA time zone names in `timeZone` option	?	?	?	No	?	?	?
`toLocaleFormat`	No	No	No	4 — 58	No	No	No
`toLocaleString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toLocaleString.locales`	No	26	?	56	No	10	Yes
`toLocaleString.options`	No	26	?	56	No	10	Yes
`toLocaleString`: IANA time zone names in `timeZone` option	?	?	?	No	?	?	?
`toLocaleTimeString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toLocaleTimeString.locales`	No	26	?	56	No	10	Yes
`toLocaleTimeString.options`	No	26	?	56	No	10	Yes
`toLocaleTimeString`: IANA time zone names in `timeZone` option	?	?	?	No	?	?	?
`toSource`	No	No	No	4	No	No	No
`toString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toTimeString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`toUTCString`	Yes	Yes	Yes	4	Yes	Yes	Yes
`valueOf`	Yes	Yes	Yes	4	Yes	Yes	Yes

	Server
	Node.js
Basic support	Yes
`@@toPrimitive`	6.0.0
`UTC`	Yes
`getDate`	Yes
`getDay`	Yes
`getFullYear`	Yes
`getHours`	Yes
`getMilliseconds`	Yes
`getMinutes`	Yes
`getMonth`	Yes
`getSeconds`	Yes
`getTime`	Yes
`getTimezoneOffset`	Yes
`getUTCDate`	Yes
`getUTCDay`	Yes
`getUTCFullYear`	Yes
`getUTCHours`	Yes
`getUTCMilliseconds`	Yes
`getUTCMinutes`	Yes
`getUTCMonth`	Yes
`getUTCSeconds`	Yes
`getYear`	Yes
`now`	Yes
`parse`	Yes
`parse`: ISO 8601 format	?
`prototype`	Yes
`prototype`: Ordinary object (ES2015)	?
`setDate`	Yes
`setFullYear`	Yes
`setHours`	Yes
`setMilliseconds`	Yes
`setMinutes`	Yes
`setMonth`	Yes
`setSeconds`	Yes
`setTime`	Yes
`setUTCDate`	Yes
`setUTCFullYear`	Yes
`setUTCHours`	Yes
`setUTCMilliseconds`	Yes
`setUTCMinutes`	Yes
`setUTCMonth`	Yes
`setUTCSeconds`	Yes
`setYear`	Yes
`toDateString`	Yes
`toGMTString`	Yes
`toISOString`	Yes
`toJSON`	Yes
`toLocaleDateString`	?
`toLocaleDateString.locales`	?
`toLocaleDateString.options`	?
`toLocaleDateString`: IANA time zone names in `timeZone` option	?
`toLocaleFormat`	No
`toLocaleString`	?
`toLocaleString.locales`	?
`toLocaleString.options`	?
`toLocaleString`: IANA time zone names in `timeZone` option	?
`toLocaleTimeString`	?
`toLocaleTimeString.locales`	?
`toLocaleTimeString.options`	?
`toLocaleTimeString`: IANA time zone names in `timeZone` option	?
`toSource`	No
`toString`	Yes
`toTimeString`	Yes
`toUTCString`	Yes
`valueOf`	Yes

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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date