Javascript 如何在javascript中获得当年的第一天？

How to get first day of current year in javascript?

提问by user1990525

I need javascript code to get first day of year. e.g. It will be 1st Jan 2013 for this year.

我需要 javascript 代码才能获得一年的第一天。例如，今年将是 2013 年 1 月 1 日。

For next year it should be 1st Jan 2014. So basically 1st day of whatever is current year.

明年应该是 2014 年 1 月 1 日。所以基本上是今年的第一天。

回答by Guffa

Create a new Dateinstance to get the current date, use getFullYearto get the year from that, and create a Dateintance with the year, month 0 (January), and date 1:

创建一个新Date实例以获取当前日期，用于getFullYear从中获取年份，并创建一个Date包含年份、月份 0（一月）和日期 1的实例：

var d = new Date(new Date().getFullYear(), 0, 1);

回答by Moritz Roessler

var year = 2013;

var date = new Date(year, 0, 1);

console.log(date); // Tue Jan 01 2013 00:00:00 GMT+0100 (Mitteleurop?ische Zeit)

You can construct Dates using new Date(YEAR,MONTH,DAY)

您可以使用构造日期 new Date(YEAR,MONTH,DAY)

So giving the constructor the yearyou want and the first Day of the First Month, you get your Date Object

所以给构造函数year你想要的和第一个月的第一天，你得到你的日期对象

Note that the Date Object starts counting with 0 for the Month, so January == 0

请注意，日期对象从 0 开始计算月份，因此一月 == 0

回答by Nick

Try this one:

试试这个：

var timestmp = new Date().setFullYear(new Date().getFullYear(), 0, 1);
var yearFirstDay = Math.floor(timestmp / 86400000);
var day = new Date(yearFirstDay);
alert(day.getDay());

Note: that code returns number, so Sunday is 0, Monday is 1, and so on.

注意：该代码返回数字，因此星期日为 0，星期一为 1，依此类推。

回答by Nick

var d = new Date(2013, 0, 1).getDay(); //0 is January for some reason

alert(d);

回答by Jacob George

Check out this fiddle

看看这个小提琴

year = prompt("Enter year : ");

d = new Date(year, 0,1);

var myDays=["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"];

alert("First Day is " + myDays[d.getDay()]);