从星期数和年份在javascript中获取星期五

问题描述：

我有周数和年份，需要在该周和年份中找出日期（星期五）。

I have week number and year, need to find out date (friday) in that week and year.

function getFriday(week_num, year)
{
    ?

    return friday_date_object;
}

我该怎么做？

答

第1周是第一个星期四的星期。

The week #1 is the week with the first Thursday.

这是一个函数来获取任何一天：

Here is a function to get any day:

var w2date = function(year, wn, dayNb){
    var j10 = new Date( year,0,10,12,0,0),
        j4 = new Date( year,0,4,12,0,0),
        mon1 = j4.getTime() - j10.getDay() * 86400000;
    return new Date(mon1 + ((wn - 1)  * 7  + dayNb) * 86400000);
};
console.log(w2date(2010, 1, 4));

周数从1开始，直到52或53，这取决于年份。

对于日数，0是星期一，1是星期二，...和4是星期五

week numbers start at 1 until 52 or 53 it depends the year.
For the day numbers, 0 is Monday, 1 is Tuesday, ... and 4 is Friday

从星期数和年份在javascript中获取星期五

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