Date.parse()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The Date.parse() static method parses a string representation of a date, and returns the date's timestamp.

Only the date time string format is explicitly specified to be supported. Other formats are implementation-defined and may not work across all browsers. A library can help if many different formats are to be accommodated.

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Syntax

js
Date.parse(dateString)

Parameters

dateString

A string in the date time string format. See the linked reference for caveats on using different formats.

Return value

A number representing the timestamp of the given date. If dateString fails to be parsed as a valid date, NaN is returned.

Description

This function is useful for setting date values based on string values, for example in conjunction with the setTime() method.

Because parse() is a static method of Date, you always use it as Date.parse(), rather than as a method of a Date object you created.

Examples

Using Date.parse()

The following calls all return 1546300800000. The first will imply UTC time because it's date-only, and the others explicitly specify the UTC timezone.

js
Date.parse("2019-01-01");
Date.parse("2019-01-01T00:00:00.000Z");
Date.parse("2019-01-01T00:00:00.000+00:00");

The following call, which does not specify a time zone will be set to 2019-01-01 at 00:00:00 in the local timezone of the system, because it has both date and time.

js
Date.parse("2019-01-01T00:00:00");

Non-standard date strings

Note: This section contains implementation-specific behavior that can be inconsistent across implementations.

Implementations usually default to the local time zone when the date string is non-standard. For consistency, we will assume that the code uses the UTC timezone.

Note: The local time zone offset comes from the system setting of the device and is then applied to the date being parsed. Daylight Saving Time (DST), of the local time zone, can also have an effect on this too.

js
Date.parse("Jan 1, 1970"); // 0 in all implementations

Date.parse("Thu, 01 Jan 1970 00:00:00"); // 0 in all implementations

Date.parse("1970,1,1"); // 0 in Chrome and Firefox, NaN in Safari

Date.parse("02 01 1970");
// 2678400000 in Chrome and Firefox (Sun Feb 01 1970 00:00:00 GMT+0000);
// NaN in Safari

// With explicit timezone
Date.parse("Thu, 01 Jan 1970 00:00:00 GMT+0300");
// -10800000 in all implementations in all timezones

// Single number
Date.parse("0");
// NaN in Firefox ≤122
// 946684800000 in Chrome and Firefox ≥123  (Sat Jan 01 2000 00:00:00 GMT+0000);
// -62167219200000 in Safari (Sat Jan 01 0000 00:00:00 GMT+0000)

// Two-digit number that may be a month
Date.parse("28");
// NaN Chrome and Firefox
// -61283606400000 in Safari (Fri Dec 31 0027 23:58:45 GMT-0001)

// Two-digit year
Date.parse("70/01/01"); // 0 in all implementations

// Out-of-bounds date components
Date.parse("2014-25-23"); // NaN in all implementations
Date.parse("Mar 32, 2014"); // NaN in all implementations
Date.parse("2014/25/23"); // NaN in all implementations

Date.parse("2014-02-30");
// NaN in Safari
// 1393718400000 in Chrome and Firefox (Sun Mar 02 2014 00:00:00 GMT+0000)
Date.parse("02/30/2014"); // 1393718400000 in all implementations

// Chrome, Safari, and Firefox 122 and later parse only the first three letters for the month.
// FF121 and earlier parse first three letters and any substring up to the correct month name.
Date.parse("04 Dec 1995"); // 818031600000 in all implementations
Date.parse("04 Decem 1995"); // 818031600000 in all implementations
Date.parse("04 December 1995"); // 818031600000 in all implementations
Date.parse("04 DecFoo 1995"); // NaN in Firefox 121 and earlier. 818031600000 in other implementations
Date.parse("04 De 1995"); // NaN in all implementations

Specifications

Specification
ECMAScript Language Specification
# sec-date.parse

Browser compatibility

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See also