在JavaScript中获取星期几

Question

I would like to get the first day and last day in the week using JavaScript.

For example, today is 2016-13-12.

FD = 2016-11-12 LD = 2016-17-12

How can I get the FD and LD? I tried using this code,

Date.prototype.GetFirstDayOfWeek = function() {
        return (new Date(this.setDate(this.getDate() - this.getDay())));
    }

    Date.prototype.GetLastDayOfWeek = function() {
        return (new Date(this.setDate(this.getDate() - this.getDay() +6)));
    }
    var today = new Date();

It is working but I want to format it in "2016-12-11". Also I would like also to change the date into a past or future. For example, If I click the button "<" it will go past 1 week. then if the user click again the button, it will get the next last week. and so on.

Scenario: DAtes now is 2016-11-12 - 2016-17-12 When the user click button "<". it will become 2016-04-12 - 2016-10-12

Answer 1

You can use script below to find firstDay and lastDay of current week;

//0=Sunday, 1=Monday
var d = new Date(); 
var day = d.getDay();

var firstDayOW = d.getDate() - day + (day == 0 ? -6:1); 
firstDay = new Date(d.setDate(firstDay));

var lastDayOW = firstDay + 6; 
lastDayOW = new Date(d.setDate(lastDayOW));

I hope this helps you.

Kind regards.

Answer 2

var curr = new Date; // get current date
    var first = curr.getDate() - curr.getDay(); // First day is the day of the month - the day of the week
    var last = first + 6; // last day is the first day + 6

    var firstday = new Date(curr.setDate(first)).toUTCString();
    var lastday = new Date(curr.setDate(last)).toUTCString();