Date.prototype.toLocaleString() - JavaScript 编辑

The toLocaleString() method returns a string with a language sensitive representation of this date.

The new locales and options arguments let applications specify the language whose formatting conventions should be used and customize the behavior of the function.

In older implementations, which ignore the locales and options arguments, the locale used and the form of the string returned are entirely implementation-dependent.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

dateObj.toLocaleString([locales[, options]])

Parameters

The locales and options arguments customize the behavior of the function and let applications specify the language whose formatting conventions should be used. In implementations, which ignore the locales and options arguments, the locale used and the form of the string returned are entirely implementation dependent.

See the Intl.DateTimeFormat() constructor for details on these parameters and how to use them.

The default value for each date-time component property is undefined. But, if the weekday, year, month, and day properties are all undefined, then year, month, and day are assumed to be "numeric".

Return value

A string representing the given date according to language-specific conventions.

Performance

When formatting large numbers of dates, it is better to create an Intl.DateTimeFormat object and use the function provided by its format property.

Examples

Using toLocaleString()

In basic use without specifying a locale, a formatted string in the default locale and with default options is returned.

let date = new Date(Date.UTC(2012, 11, 12, 3, 0, 0));

// toLocaleString() without arguments depends on the
// implementation, the default locale, and the default time zone
console.log(date.toLocaleString());
// → "12/11/2012, 7:00:00 PM" if run in en-US locale with time zone America/Los_Angeles

Checking for support for locales and options arguments

The locales and options arguments are not supported in all browsers yet. To check whether an implementation supports them already, you can use the requirement that illegal language tags are rejected with a RangeError exception:

function toLocaleStringSupportsLocales() {
  try {
    new Date().toLocaleString('i');
  } catch (e) {
    return e instanceof RangeError;
  }
  return false;
}

Using locales

This example shows some of the variations in localized date and time formats. In order to get the format of the language used in the user interface of your application, make sure to specify that language (and possibly some fallback languages) using the locales argument:

let date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// formats below assume the local time zone of the locale;
// America/Los_Angeles for the US

// US English uses month-day-year order and 12-hour time with AM/PM
console.log(date.toLocaleString('en-US'));
// → "12/19/2012, 7:00:00 PM"

// British English uses day-month-year order and 24-hour time without AM/PM
console.log(date.toLocaleString('en-GB'));
// → "20/12/2012 03:00:00"

// Korean uses year-month-day order and 12-hour time with AM/PM
console.log(date.toLocaleString('ko-KR'));
// → "2012. 12. 20. 오후 12:00:00"

// Arabic in most Arabic speaking countries uses real Arabic digits
console.log(date.toLocaleString('ar-EG'));
// → "٢٠‏/١٢‏/٢٠١٢ ٥:٠٠:٠٠ ص"

// for Japanese, applications may want to use the Japanese calendar,
// where 2012 was the year 24 of the Heisei era
console.log(date.toLocaleString('ja-JP-u-ca-japanese'));
// → "24/12/20 12:00:00"

// When requesting a language that may not be supported, such as
// Balinese, include a fallback language (in this case, Indonesian)
console.log(date.toLocaleString(['ban', 'id']));
// → "20/12/2012 11.00.00"

Using options

The results provided by toLocaleString() can be customized using the options argument:

let date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// request a weekday along with a long date
let options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };

console.log(date.toLocaleString('de-DE', options));
// → "Donnerstag, 20. Dezember 2012"

// an application may want to use UTC and make that visible
options.timeZone = 'UTC';
options.timeZoneName = 'short';

console.log(date.toLocaleString('en-US', options));
// → "Thursday, December 20, 2012, GMT"

// sometimes even the US needs 24-hour time
console.log(date.toLocaleString('en-US', { hour12: false }));
// → "12/19/2012, 19:00:00"

Avoid comparing formatted date values to static values

Most of the time, the formatting returned by toLocaleString() is consistent. However, this might change in the future, and isn't guaranteed for all languages; output variations are by design, and allowed by the specification.

Most notably, the IE and Edge browsers insert bidirectional control characters around dates, so the output text will flow properly when concatenated with other text.

For this reason, you cannot expect to be able to compare the results of toLocaleString() to a static value:

"1/1/2019, 01:00:00" === new Date("2019-01-01T01:00:00Z").toLocaleString("en-US");
// true in Firefox and others
// false in IE and Edge

Note: See also this StackOverflow thread for more details and examples.

Specifications

Browser compatibility

BCD tables only load in the browser

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

See also

• Intl.DateTimeFormat
• Date.prototype.toLocaleDateString()
• Date.prototype.toLocaleTimeString()
• Date.prototype.toString()