JS: Date Tutorial

By Xah Lee. Date: . Last updated: .

Quick usage code example

// create a date object of current date time
const xdate = new Date();

const hh = xdate.getHours();
const mm = xdate.getMinutes();
const ss = xdate.getSeconds();

console.log(hh + ":" + mm + ":" + ss);
// 8:15:51
console.log(xdate.getFullYear());
// 2020

console.log(xdate.getDate());
// 6
// first day of month is 1

console.log(xdate.getMonth());
// 8
// warning: Jan is 0, Feb is 1, etc

console.log(xdate.getDay());
// 0
// Sunday is 0. Saturday is 6

Create Date Object (of current date)

console.log(new Date());
// 2026-02-04T05:54:31.574Z

Create Date Object (of specific date), parse date

ISO date string to milliseconds

// ISO date string to milliseconds
console.log(Date.parse("2026-02-03T21:57:23-0800"));
// 1770184643000

Milliseconds to date object

// ISO date string to milliseconds
console.log(Date.parse("2026-02-03T21:57:23-0800"));
// 1770184643000

console.log(new Date(1770184643000));
// 2026-02-04T05:57:23.000Z

Date object to milliseconds

const xdate = new Date();
console.log(xdate.getTime());
// 1770247765861

Print date in different formats

// print date in different formats

console.log((new Date()).toLocaleString());
// 2/3/2026, 10:13:50 PM

console.log((new Date()).toLocaleDateString());
// 2/3/2026

console.log((new Date()).toLocaleTimeString());
// 10:14:35 PM

console.log((new Date()).toDateString());
// Tue Feb 03 2026

console.log((new Date()).toTimeString());
// 22:15:03 GMT-0800 (Pacific Standard Time)

console.log((new Date()).toISOString());
// 2026-02-04T06:15:14.346Z

console.log((new Date()).toUTCString());
// Wed, 04 Feb 2026 06:15:24 GMT

console.log((new Date()).toString());
// Tue Feb 03 2026 22:16:12 GMT-0800 (Pacific Standard Time)

What is the difference between UTC and GMT?

For practical purposes, they are the same.

UTC (Coordinated Universal Time) is a time standard based on atomic clock.

GMT (Greenwich Mean Time) is a older time standard.

“Zulu time” is a term used in military and is the same as GMT. (GMT and UTC has a abbrev of Z, because Z is like zero. Z in NATO phonetic alphabet is read as Zulu. That's why GMT/UTC is also said Zulu time. )

JavaScript. Date