date.toLocaleString

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

var 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

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

var 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"

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

// request a weekday along with a long date
var 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"