建立一個新的 Date 物件

Created: November-22, 2018

要建立新的 Date 物件，請使用 Date() 建構函式：

沒有爭論

Date() 建立一個包含當前時間（最長毫秒）和日期的 Date 例項。
有一個整數引數

Date(m) 建立一個 Date 例項，其中包含與 Epoch 時間（1970 年 1 月 1 日，1970 年 1 月 1 日）加上 m 毫秒相對應的時間和日期。示例：new Date(749019369738) 給出日期 Sun，26 Sep 1993 04:56:09 GMT 。
帶字串引數

Date(dateString) 返回 dateString 後使用 Date.parse 解析 dateString 後得到的 Date 物件。
有兩個或多個整數引數

Date(i1, i2, i3, i4, i5, i6) 將引數讀取為年，月，日，小時，分鐘，秒，毫秒並例項化相應的 Date 物件。請注意，月份在 JavaScript 中為 0 索引，因此 0 表示 1 月，11 表示 12 月。示例：new Date(2017, 5, 1) 於 2017 年 6 月 1 日釋出。

探索日期

請注意，這些示例是在夏令時期間在美國中部時區的瀏覽器上生成的，如程式碼所示。與 UTC 的比較具有指導意義，Date.prototype.toISOString() 用於顯示 UTC 的日期和時間（格式化字串中的 Z 表示 UTC）。

// Creates a Date object with the current date and time from the 
// user's browser
var now = new Date();
now.toString() === 'Mon Apr 11 2016 16:10:41 GMT-0500 (Central Daylight Time)' 
// true
// well, at the time of this writing, anyway

// Creates a Date object at the Unix Epoch (i.e., '1970-01-01T00:00:00.000Z')
var epoch = new Date(0);
epoch.toISOString() === '1970-01-01T00:00:00.000Z' // true

// Creates a Date object with the date and time 2,012 milliseconds 
// after the Unix Epoch (i.e., '1970-01-01T00:00:02.012Z').
var ms = new Date(2012); 
date2012.toISOString() === '1970-01-01T00:00:02.012Z' // true

// Creates a Date object with the first day of February of the year 2012 
// in the local timezone.
var one = new Date(2012, 1);
one.toString() === 'Wed Feb 01 2012 00:00:00 GMT-0600 (Central Standard Time)' 
// true

// Creates a Date object with the first day of the year 2012 in the local 
// timezone.
// (Months are zero-based) 
var zero = new Date(2012, 0);
zero.toString() === 'Sun Jan 01 2012 00:00:00 GMT-0600 (Central Standard Time)' 
// true

// Creates a Date object with the first day of the year 2012, in UTC.
var utc = new Date(Date.UTC(2012, 0));
utc.toString() === 'Sat Dec 31 2011 18:00:00 GMT-0600 (Central Standard Time)'
// true
utc.toISOString() === '2012-01-01T00:00:00.000Z'
// true

// Parses a string into a Date object (ISO 8601 format added in ECMAScript 5.1)
// Implementations should assumed UTC because of ISO 8601 format and Z designation
var iso = new Date('2012-01-01T00:00:00.000Z');
iso.toISOString() === '2012-01-01T00:00:00.000Z' // true

// Parses a string into a Date object (RFC in JavaScript 1.0)
var local = new Date('Sun, 01 Jan 2012 00:00:00 -0600');
local.toString() === 'Sun Jan 01 2012 00:00:00 GMT-0600 (Central Standard Time)'
// true

// Parses a string in no particular format, most of the time. Note that parsing
// logic in these cases is very implementation-dependent, and therefore can vary
// across browsers and versions.
var anything = new Date('11/12/2012'); 
anything.toString() === 'Mon Nov 12 2012 00:00:00 GMT-0600 (Central Standard Time)'
// true, in Chrome 49 64-bit on Windows 10 in the en-US locale. Other versions in 
// other locales may get a different result.

// Rolls values outside of a specified range to the next value.
var rollover = new Date(2012, 12, 32, 25, 62, 62, 1023);
rollover.toString() === 'Sat Feb 02 2013 02:03:03 GMT-0600 (Central Standard Time)'
// true; note that the month rolled over to Feb; first the month rolled over to 
// Jan based on the month 12 (11 being December), then again because of the day 32
// (January having 31 days).

// Special dates for years in the range 0-99
var special1 = new Date(12, 0);
special1.toString() === 'Mon Jan 01 1912 00:00:00 GMT-0600 (Central Standard Time)`
// true

// If you actually wanted to set the year to the year 12 CE, you'd need to use the
// setFullYear() method:
special1.setFullYear(12);
special1.toString() === 'Sun Jan 01   12 00:00:00 GMT-0600 (Central Standard Time)`
// true