Date.prototype.setFullYear()

The setFullYear() method of {{jsxref("Date")}} instances changes the year, month, and/or day of month for this date according to local time.

{{InteractiveExample("JavaScript Demo: Date.prototype.setFullYear()")}}

```js interactive-example const event = new Date("August 19, 1975 23:15:30");

event.setFullYear(1969);

console.log(event.getFullYear()); // Expected output: 1969

event.setFullYear(0);

console.log(event.getFullYear()); // Expected output: 0

## Syntax

```js-nolint
setFullYear(yearValue)
setFullYear(yearValue, monthValue)
setFullYear(yearValue, monthValue, dateValue)

Parameters#

• yearValue
• : An integer representing the year. For example, 1995.
• monthValue {{optional_inline}}
• : An integer representing the month: 0 for January, 1 for February, and so on.
• dateValue {{optional_inline}}
• : An integer between 1 and 31 representing the day of the month. If you specify dateValue, you must also specify monthValue.

Return value#

Changes the {{jsxref("Date")}} object in place, and returns its new timestamp. If a parameter is NaN (or other values that get coerced to NaN, such as undefined), the date is set to Invalid Date and NaN is returned.

Description#

If you do not specify the monthValue and dateValue parameters, the same values as what are returned by {{jsxref("Date/getMonth", "getMonth()")}} and {{jsxref("Date/getDate", "getDate()")}} are used.

If a parameter you specify is outside of the expected range, other parameters and the date information in the {{jsxref("Date")}} object are updated accordingly. For example, if you specify 15 for monthValue, the year is incremented by 1 (yearValue + 1), and 3 is used for the month.

Because setFullYear() operates on the local time, crossing a Daylight Saving Time (DST) boundary may result in a different elapsed time than expected. For example, if setting the date crosses a spring-forward transition (losing an hour), the difference in timestamps between the new and old date is one hour less than the nominal day difference multiplied by 24 hours. Conversely, crossing a fall-back transition (gaining an hour) result in an extra hour. If you need to adjust the date by a fixed amount of time, consider using {{jsxref("Date/setUTCFullYear", "setUTCFullYear()")}} or {{jsxref("Date/setTime", "setTime()")}}.

If the new local time falls within an offset transition, the exact time is derived using the same behavior as Temporal's disambiguation: "compatible" option. That is, if the local time corresponds to two instants, the earlier one is chosen; if the local time does not exist (there is a gap), we go forward by the gap duration.

Examples#

Using setFullYear()#

const theBigDay = new Date();
theBigDay.setFullYear(1997);

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Date.prototype.getUTCFullYear()")}}
• {{jsxref("Date.prototype.setUTCFullYear()")}}
• {{jsxref("Date.prototype.setYear()")}}