Date.prototype.getDay()

¥Syntax

getDay()

¥Parameters

没有任何。

¥None.

¥Return value

0 到 6 之间的整数，表示根据当地时间给定日期是星期几：0 表示星期日，1 表示星期一，2 表示星期二，依此类推。如果日期是 invalid，则返回 NaN。

¥An integer, between 0 and 6, representing the day of the week for the given date according to local time: 0 for Sunday, 1 for Monday, 2 for Tuesday, and so on. Returns NaN if the date is invalid.

¥Description

getDay() 的返回值从零开始，这对于索引日期数组很有用，例如：

¥The return value of getDay() is zero-based, which is useful for indexing into arrays of days, for example:

const valentines = new Date("1995-02-14");
const day = valentines.getDay();
const dayNames = ["Sunday", "Monday", "Tuesday" /* , … */];

console.log(dayNames[day]); // "Monday"

但是，出于国际化的目的，你应该更喜欢使用 Intl.DateTimeFormat 和 options 参数。

¥However, for the purpose of internationalization, you should prefer using Intl.DateTimeFormat with the options parameter instead.

const options = { weekday: "long" };
console.log(new Intl.DateTimeFormat("en-US", options).format(valentines));
// "Monday"
console.log(new Intl.DateTimeFormat("de-DE", options).format(valentines));
// "Montag"

¥Examples

¥Using getDay()

基于 Date 对象 xmas95 的值，weekday 变量的值为 1，因为 1995 年 12 月 25 日是星期一。

¥The weekday variable has value 1, based on the value of the Date object xmas95, because December 25, 1995 is a Monday.

const xmas95 = new Date("1995-12-25T23:15:30");
const weekday = xmas95.getDay();

console.log(weekday); // 1

¥See also

• Date.prototype.getUTCDate()
• Date.prototype.getUTCDay()
• Date.prototype.setDate()