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issue with getting special day [duplicate]

I have an date, i need to add no. of days to get future date but weekends should be excluded.
i.e
input date = "9-DEC-2011";
No. of days to add = '13';
next date should be "28-Dec-2011"
Here weekends(sat/sun) are not counted.

Try this
var startDate = "9-DEC-2011";
startDate = new Date(startDate.replace(/-/g, "/"));
var endDate = "", noOfDaysToAdd = 13, count = 0;
while(count < noOfDaysToAdd){
endDate = new Date(startDate.setDate(startDate.getDate() + 1));
if(endDate.getDay() != 0 && endDate.getDay() != 6){
//Date.getDay() gives weekday starting from 0(Sunday) to 6(Saturday)
count++;
}
}
alert(endDate);//You can format this date as per your requirement
Working Demo

#ShankarSangoli
Here's a newer version which avoid recreating a Date object on each loop, note that it's wrapped in a function now.
function calcWorkingDays(fromDate, days) {
var count = 0;
while (count < days) {
fromDate.setDate(fromDate.getDate() + 1);
if (fromDate.getDay() != 0 && fromDate.getDay() != 6) // Skip weekends
count++;
}
return fromDate;
}
alert(calcWorkingDays(new Date("9/DEC/2011"), 13));

Here is an elegant solution without any looping or external library:
function addBusinessDaysToDate(date, days) {
var day = date.getDay();
date = new Date(date.getTime());
date.setDate(date.getDate() + days + (day === 6 ? 2 : +!day) + (Math.floor((days - 1 + (day % 6 || 1)) / 5) * 2));
return date;
}
var date = "9-DEC-2011";
var newDate = addBusinessDaysToDate(new Date(date.replace(/-/g, "/")), 13);
console.log(newDate.toString().replace(/\S+\s(\S+)\s(\d+)\s(\d+)\s.*/, '$2-$1-$3')); // alerts "28-Dec-2011"

or you can be like this
function addWeekdays(date, weekdays) {
var newDate = new Date(date.getTime());
var i = 0;
while (i < weekdays) {
newDate.setDate(newDate.getDate() + 1);
var day = newDate.getDay();
if (day > 1 && day < 7) {
i++;
}
}
return newDate;
}
var currentDate = new Date('10/31/2014');
var targetDate = addWeekdays(currentDate, 45);
alert(targetDate);

Using moment.js:
const DATE_FORMAT = 'D-MMM-YYYY';
const SUNDAY = 0; // moment day index
const SATURDAY = 6; // moment day index
const WEEKENDS = [SATURDAY, SUNDAY];
function addBusinessDays(stringDate, numberOfDays, dateFormat = DATE_FORMAT) {
const date = moment(stringDate, dateFormat);
let count = 0;
while (count < numberOfDays) {
date.add(1, 'day');
// Skip weekends
if (WEEKENDS.includes(date.day())) {
continue;
}
// Increment count
count++;
}
return date.format(dateFormat);
}
// Test cases
console.log(addBusinessDays('3-Mar-2021', 1)); // 4-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 2)); // 5-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 3)); // 8-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 4)); // 9-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 5)); // 10-Mar-2021
console.log(addBusinessDays('9-Dec-2011', 13)); // 28-Dec-2011
console.log(addBusinessDays('10-Dec-2011', 13)); // 28-Dec-2011 (Saturday, so remain on Friday)
console.log(addBusinessDays('11-Dec-2011', 13)); // 28-Dec-2011 (Sunday, so remain on Friday)
console.log(addBusinessDays('12-Dec-2011', 13)); // 29-Dec-2011
console.log(addBusinessDays('13-Dec-2011', 13)); // 30-Dec-2011
console.log(addBusinessDays('14-Dec-2011', 13)); // 2-Jan-2012
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>

This question is quite old, but all the previous answers are iterating over the days one by one. That could be inefficient for a large number of days. This works for me, assuming days is a positive int and the startDate is a working day:
function addWorkingDates(startDate, days) {
const current_day = startDate.getDay() - 1; // Week day, starting on Monday
const weekend_days = 2 * parseInt((current_day + days) / 5);
startDate.setDate(changed_to.getDate() + days + weekend_days);
}
addWorkingDates(new Date(),5)

For some reason it was more intuitive to me to try this recursively. This version doesn't account for holidays, but you could change the isValid function to check whatever.
function addWeekdaysToDate(date, numberToAdd) {
var isValid = function(d) { return d.getDay() !== 0 && d.getDay() !== 6 }
if(Math.abs(numberToAdd) > 1) {
return addWeekdaysToDate(
addWeekdaysToDate(date, Math.sign(numberToAdd)),
numberToAdd - Math.sign(numberToAdd)
)
} else if(Math.abs(numberToAdd) === 1) {
var result = new Date(date)
result.setDate(result.getDate() + Math.sign(numberToAdd))
if(isValid(result)) {
return result
} else {
return addWeekdaysToDate(result, Math.sign(numberToAdd))
}
} else if(numberToAdd === 0) {
return date
}
return false
}
console.log(addWeekdaysToDate(new Date(), 1))
console.log(addWeekdaysToDate(new Date(), 5))
console.log(addWeekdaysToDate(new Date(), -7))
In certain browsers you may need a polyfill for Math.sign:
Math.sign = Math.sign || function(x) {
x = +x; // convert to a number
if (x === 0 || isNaN(x)) {
return Number(x);
}
return x > 0 ? 1 : -1;
}

try this solution
<script language="javascript">
function getDateExcludeWeekends(startDay, startMonth, startYear, daysToAdd) {
var sdate = new Date();
var edate = new Date();
var dayMilliseconds = 1000 * 60 * 60 * 24;
sdate.setFullYear(startYear,startMonth,startDay);
edate.setFullYear(startYear,startMonth,startDay+daysToAdd);
var weekendDays = 0;
while (sdate <= edate) {
var day = sdate.getDay()
if (day == 0 || day == 6) {
weekendDays++;
}
sdate = new Date(+sdate + dayMilliseconds);
}
sdate.setFullYear(startYear,startMonth,startDay + weekendDays+daysToAdd);
return sdate;
}
</script>

If you want to get the next working day, from a specific date, use the following code...
function getNextWorkingDay(originalDate) {
var nextWorkingDayFound = false;
var nextWorkingDate = new Date();
var dateCounter = 1;
while (!nextWorkingDayFound) {
nextWorkingDate.setDate(originalDate.getDate() + dateCounter);
dateCounter++;
if (!isDateOnWeekend(nextWorkingDate)) {
nextWorkingDayFound = true;
}
}
return nextWorkingDate;
}
function isDateOnWeekend(date) {
if (date.getDay() === 6 || date.getDay() === 0)
return true;
else
return false;
}

Try this
function calculate() {
var noOfDaysToAdd = 13;
var startDate = "9-DEC-2011";
startDate = new Date(startDate.replace(/-/g, "/"));
var endDate = "";
count = 0;
while (count < noOfDaysToAdd) {
endDate = new Date(startDate.setDate(startDate.getDate() + 1));
if (endDate.getDay() != 0 && endDate.getDay() != 6) {
count++;
}
}
document.getElementById("result").innerHTML = endDate;
}
<div>
Date of book delivery: <span id="result"></span><br /><br />
<input type="button" onclick="calculate();" value="Calculate" />
<br>
<br>
</div>

Year Converter Function

i'm trying to make a function where you input a year, and the output return the centure that year is from. I got most of down, but somewhere in the logic i'm missing something and i'm not getting the correct values for when the year is, i.e. 2000 (20th century, and i get 21st)
My JS:
function centuryFromYear(year) {
if (year <= 100) {
console.log("um")
return year * 0 + 1
} else if (year > 100 && year <= 1000) {
console.log("dois")
var kek = year / 100
var lul = Math.floor(kek)
} else if (year > 1001) {
console.log("tres")
var kek = year / 100
var lul = Math.floor(kek)
return (lul + 1)
}
}

May be this:
function centuryFromYear(year) {
return Math.floor((year - 1) / 100) + 1;
}
//* tests
[100,101,250, 1000, 1001, 1999, 2000, 2001].forEach(function(y) {
console.log(y + ' year is in ' + centuryFromYear(y) + ' century');
});

Apologies for a slightly messy approach, I am sure there is possibly a more elegant approach available:
Note: negative centuries and year 0 AD do not exist on the Georgian calender
function myFunction() {
year = 2000;
b = year;
if (b % 100 > 0){
b = Math.floor((year)/100);
b = b +1 ;
}
else if (b % 100 == 0){
b = Math.floor((year)/100);
}
else if (b < 100 && b > 0){
b = (Math.floor((year)/100)+1);
}
}

First Tuesday of every Month

Hello I am trying to use the following code which is a mish mash of "lifted code" but it keeps pumping out todays date and time.
I am trying to get the date for the first Tuesday of every month at 19:00.
I am using W3C School Try-it for testing purposes.
<!DOCTYPE html>
<html>
<head>
<script>
function displayDate()
{
var myDate = new Date();
myDate.setHours(19, 00, 0, 0);
myDate.setYear(2013);
myDate.setDate(1);
myDate.setMonth();
//Find Tuesday
var tue = 2;
while(myDate.getDay() != tue) {
myDate.setDate(myDate.getDate() + 1);
}
document.write(myDate);
</script>
</head>
<body>
<h1>My First JavaScript</h1>
<p id="demo">This is a paragraph.</p>
<button type="button" onclick="displayDate()">Display Date</button>
</body>
</html>
Roy
<==Update==>
I have use your code which works well but need to factor in after the First Tuesday has happened for the next month, I have tried this if statement but breaks.
function getTuesday() {
var datenow = new Date();
var d = new Date(),
month = d.getMonth(),
tuedays= [];
d.setDate(1);
// Get the first Monday in the month
while (d.getDay() !== 2) {
d.setDate(d.getDate() + 1);
}
// Get all the other Tuesdays in the month
while (d.getMonth() === month) {
tuedays.push(new Date(d.setHours(17,00,00,00)));
d.setDate(d.getDate() + 7);
}
If (d.getDate() >= datenow.getDate)
{
d.setMonth(d.getMonth() + 1);
document.write(tuedays[1]);
}
Else
{
document.write(tuedays[1]);
}
}

Use below function, that will give you current month Tuesdays.
function getTuesday() {
var d = new Date(),
month = d.getMonth(),
tuesdays= [];
d.setDate(1);
// Get the first Monday in the month
while (d.getDay() !== 2) {
d.setDate(d.getDate() + 1);
}
// Get all the other Tuesdays in the month
while (d.getMonth() === month) {
tuesdays.push(new Date(d.getTime()));
d.setDate(d.getDate() + 7);
}
return tuesdays;
}

I know that this is old but this is a function that i wrote based on what Sahal wrote that accepts a few additional features. Ill go through the arguments and returns below.
function getDates(dayString, month, year, first, allInYear) {
if (!dayString) { console.error('Missing required parameter: dayString is required.'); return; }
if (first === undefined || first === null) { first = false; }
if (allInYear === undefined || allInYear === null) { allInYear = false; }
if (year === undefined || year === null) { year = new Date().getFullYear(); }
var converted = false;
if (month === undefined || month === null) {
var temp = new Date();
if (temp.getDate() > 9) {
month = ((temp.getMonth() + 1) == 12) ? 11 : (temp.getMonth() + 1);
} else {
month = temp.getMonth();
}
converted = true;
}
if (typeof month === "string" && isNaN(parseInt(month))) {
month = month.toLowerCase().substring(0, 3);
switch (month) {
case "jan":
month = 0;
break;
case "feb":
month = 1;
break;
case "mar":
month = 2;
break;
case "apr":
month = 3;
break;
case "may":
month = 4;
break;
case "jun":
month = 5;
break;
case "jul":
month = 6;
break;
case "aug":
month = 7;
break;
case "sep":
month = 8;
break;
case "oct":
month = 9;
break;
case "nov":
month = 10;
break;
case "dec":
month = 11;
break;
default:
var temp = new Date();
if (temp.getDate() > 9) {
month = ((temp.getMonth() + 1) == 12) ? 11 : (temp.getMonth() + 1);
} else {
month = temp.getMonth();
}
converted = true;
break;
}
} else if (typeof month === "number" || (typeof month === "string" && !isNaN(parseInt(month)))) {
month = (!converted) ? parseInt(month) - 1 : month;
}
if (typeof year === "string" && !isNaN(parseInt(year)) || typeof year === "number") {
if (parseInt(year) / 1000 > 2) {
year = parseInt(year);
} else if (parseInt(year) / 10 >= 0 && parseInt(year) / 10 < 10) {
var temp2 = new Date().getFullYear();
year = (parseInt(Math.floor(temp2 / 100)) * 100) + parseInt(year);
}
} else if (typeof year === "string" && isNaN(parseInt(year))) {
if (year === "this") {
year = new Date().getFullYear();
} else if (year === "last") {
year = new Date().getFullYear() - 1;
} else if (year === "next") {
year = new Date().getFullYear() + 1;
} else {
console.warn('Year string not recognized, falling back to current year. (this, last, next).');
year = new Date().getFullYear();
}
}
var dates = [];
//hang in there this is going to get a doosie
var d = new Date(),
dow = ["sun", "mon", "tue", "wed", "thu", "fri", "sat"],
getDow = function(sd, dowa) {
for (var i = 0; i < dowa.length; i++) {
var day = dowa[i];
if (sd.toLowerCase().substring(0, 3) == day) {
return i;
}
}
return -1;
},
di = getDow(dayString, dow),
getDIM = function(year, mon) {
var isLeap = ((year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0));
return [31, (isLeap ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][mon];
};
d.setFullYear(year);
d.setMonth(month, 1);
if (di == -1) { console.error('Range Error: Day of the week should be between sunday and saturday'); return; }
if (first && !allInYear) {
while (d.getDay() !== di) {
d.setDate(d.getDate() + 1);
}
return d;
} else if (first && allInYear) {
var tm = 0;
d.setMonth(tm, 1);
for (var i = tm; i <= 11; i++) {
while (d.getDay() !== di) {
d.setDate(d.getDate() + 1);
}
dates.push(new Date(d));
tm += 1;
d.setMonth(tm, 1);
}
return dates;
} else if (!first && !allInYear) {
var eom = getDIM(d.getFullYear(), d.getMonth());
for (var x = 1; x <= eom; x++) {
if (d.getDay() === di) {
dates.push(new Date(d));
}
d.setDate(d.getDate() + 1);
}
return dates;
} else if (!first && allInYear) {
var tm = 0;
for (var i = 0; i <= 11; i++) {
var eom = getDIM(d.getFullYear(), i),
dim = [];
d.setMonth(i, 1);
for (var x = 1; x <= eom && d.getMonth() == i; x++) {
if (d.getDay() === di) {
dim.push(new Date(d));
}
d.setDate(d.getDate() + 1);
}
dates.push(dim);
}
return dates;
} else {
return [];
}
}
So the only required argument is the day string, optionally you can set month,year,first or all in a month and all in a year or not, month and year default to current, and first and allInYear default to false, But you can set first in moth, by passing null or undefined to the month and year parameter.
month parameter accepts: null|undefined, number, or string eg 'July'
year parameter accepts: null|undefined, number 2 or 4 digit, string eg '19' or '2019' also 'last', 'this', 'next'
returns Date object,Array[Date object...], or Array[Array[Date object...]...]
This has been tested and should cover most situations...

Well, it's been over 8 years since I asked this question, and it showed up at the top result on Google for 'The first Tuesday of every month'. The original project is dead now, but I've gained more experience, I feel better placed to provide an answer.
First thing to note, is the original question wasn't obvious, and the title was just as ambiguous. The original goal, was to get the next occurrence of a first Tuesday of the month, so could be the current month, or next month depending on where you are in the month.
Because of the ambiguity in the question, I have tried to cover for those differences in interpretation in the answer.
My first function, is to get the occurrence of a specific day of the week for a given month and year. Thank you to #Amadan in the comments on one of the answers.
function GetFirstDayOfMonth(dayOfTheWeek, month, year){
const date = new Date(year, month, 1);
date.setDate(date.getDate() + ((7 + dayOfTheWeek) - date.getDay()) % 7)
return date;
}
The next function, gets the next occurrence of a first specified day of the week given a date.
function GetFirstNextFirstDayOfTheWeek(currentDate, day){
const returnValue = GetFirstDayOfMonth(day, currentDate.getMonth(), currentDate.getFullYear());
if(returnValue.getDate() < currentDate.getDate()){
return GetFirstNextFirstDayOfTheWeek(new Date(currentDate.getFullYear(), currentDate.getMonth() + 1), day);
}
return returnValue;
}
So to achieve the original question I can run the following example
const tuesday = 2;
function GetFirstNextFirstTuesday(){
return GetFirstNextFirstDayOfTheWeek(new Date(), tuesday);
}
To achieve getting the first Tuesday of a Month
const tuesday = 2;
function GetFirstTuesday(month, year){
return GetFirstDayOfMonth(tuesday, month, year);
}
And to finish getting all the first Tuesdays of a given year.
const tuesday = 2;
function GetFirstTuesdayOfEveryMonth(year){
const dates = [];
for (let index = 0; index < 12; index++) {
dates.push(GetFirstDayOfMonth(tuesday, index, year));
}
return dates;
}
function GetFirstDayOfMonth(dayOfTheWeek, month, year){
// Get the first day of the month
const date = new Date(year, month, 1);
// Set the date based on the day of the week.
date.setDate(date.getDate() + ((7 + dayOfTheWeek) - date.getDay()) % 7)
return date;
}
function GetFirstNextFirstDayOfTheWeek(currentDate, day){
const returnValue = GetFirstDayOfMonth(day, currentDate.getMonth(), currentDate.getFullYear());
if(returnValue.getDate() < currentDate.getDate()){
return GetFirstNextFirstDayOfTheWeek(new Date(currentDate.getFullYear(), currentDate.getMonth() + 1), day);
}
return returnValue;
}
const tuesday = 2;
function GetFirstTuesday(month, year){
return GetFirstDayOfMonth(tuesday, month, year);
}
function GetFirstNextFirstTuesday(){
return GetFirstNextFirstDayOfTheWeek(new Date(), tuesday);
}
function GetFirstTuesdayOfEveryMonth(year){
const dates = [];
for (let index = 0; index < 12; index++) {
dates.push(GetFirstDayOfMonth(tuesday, index, year));
}
return dates;
}
console.log(GetFirstNextFirstTuesday());
console.log(GetFirstTuesday(09, 2021));
console.log(GetFirstTuesdayOfEveryMonth(2022));
Hopefully, this can help anyone who may seem to stubble on this old post, and thank you to the people that did answer.

Find the number of business days between two dates in Microsoft Dynamics CRM 2011

All, I am trying to use javascript to setValue a integer into a field based on the dates in a start and end field. I'm not even sure what the correct syntax for finding the day of the week with CRM javascript. Here is my code so far.
function netbdays_change() {
var startday = Xrm.Page.getAttribute("new_quotestart").getValue();
var endday = Xrm.Page.getAttribute("new_quoteend").getValue();
cycletime = endday - startday;
Xrm.Page.getAttribute("new_setcycletime").setValue(cycletime);
}

Try this:
function netbdays_change() {
var startday = Xrm.Page.getAttribute("new_quotestart").getValue().getDay();
var endday = Xrm.Page.getAttribute("new_quoteend").getValue().getDay();
cycletime = endday - startday;
Xrm.Page.getAttribute("new_setcycletime").setValue(cycletime);
}
getDay() returns a 0 based representation of the day of the week.
http://www.w3schools.com/jsref/jsref_getday.asp
If you want to calculate the number of days between 2 dates, try this:
function netbdays_change() {
var startday = Xrm.Page.getAttribute("new_quotestart").getValue();
var endday = Xrm.Page.getAttribute("new_quoteend").getValue();
cycletime = Math.abs(endday - startday)
Xrm.Page.getAttribute("new_setcycletime").setValue(cycletime / 86400000);
}

I finally figured out the solution: Feel Free to use everyone. :)
function netbdays_change() {
var startdays = Xrm.Page.getAttribute("new_dateqaassigned").getValue();
var enddays = Xrm.Page.getAttribute("new_quotecomplete").getValue();
var cycletime = Math.abs(enddays - startdays) / 86400000; // This first part now works
startday = Xrm.Page.getAttribute("new_dateqaassigned").getValue().getDay();
endday = Xrm.Page.getAttribute("new_quotecomplete").getValue().getDay();
var x = startday; // day of the week
var y = 0; // number of business days for output
var z = 0; // augment up to the total number of days
while (x <= 7 && z <= cycletime) {
if (x > 0 && x < 6) {
y++;
}
x++;
z++;
}
x = 0;
while (x <= 7 && z <= cycletime) {
if (x > 0 && x < 6) {
y++;
}
x++;
z++;
if (x == 6) {
x = 0;
}
}
Xrm.Page.getAttribute("new_quotetotalcycletime").setValue(y);
}

Here's my code:
function GetBusinessDays(startDate, endDate)
{
if (startDate != null && endDate != null)
{
var cycletime = (Math.abs(endDate - startDate) / 86400000) + 1;
var startday = startDate.getDay();
var x = startday; // day of the week
var y = 0; // number of business days for output
var z = 0; // augment up to the total number of days
while (z < cycletime) {
if (x > 0 && x < 6)
{
y++;
}
x++;
z++;
if (x > 6)
{
x = 0;
}
}
return y;
}
return null;
}

Add no. of days in a date to get next date(excluding weekends)

I have an date, i need to add no. of days to get future date but weekends should be excluded.
i.e
input date = "9-DEC-2011";
No. of days to add = '13';
next date should be "28-Dec-2011"
Here weekends(sat/sun) are not counted.

Try this
var startDate = "9-DEC-2011";
startDate = new Date(startDate.replace(/-/g, "/"));
var endDate = "", noOfDaysToAdd = 13, count = 0;
while(count < noOfDaysToAdd){
endDate = new Date(startDate.setDate(startDate.getDate() + 1));
if(endDate.getDay() != 0 && endDate.getDay() != 6){
//Date.getDay() gives weekday starting from 0(Sunday) to 6(Saturday)
count++;
}
}
alert(endDate);//You can format this date as per your requirement
Working Demo

#ShankarSangoli
Here's a newer version which avoid recreating a Date object on each loop, note that it's wrapped in a function now.
function calcWorkingDays(fromDate, days) {
var count = 0;
while (count < days) {
fromDate.setDate(fromDate.getDate() + 1);
if (fromDate.getDay() != 0 && fromDate.getDay() != 6) // Skip weekends
count++;
}
return fromDate;
}
alert(calcWorkingDays(new Date("9/DEC/2011"), 13));

Here is an elegant solution without any looping or external library:
function addBusinessDaysToDate(date, days) {
var day = date.getDay();
date = new Date(date.getTime());
date.setDate(date.getDate() + days + (day === 6 ? 2 : +!day) + (Math.floor((days - 1 + (day % 6 || 1)) / 5) * 2));
return date;
}
var date = "9-DEC-2011";
var newDate = addBusinessDaysToDate(new Date(date.replace(/-/g, "/")), 13);
console.log(newDate.toString().replace(/\S+\s(\S+)\s(\d+)\s(\d+)\s.*/, '$2-$1-$3')); // alerts "28-Dec-2011"

or you can be like this
function addWeekdays(date, weekdays) {
var newDate = new Date(date.getTime());
var i = 0;
while (i < weekdays) {
newDate.setDate(newDate.getDate() + 1);
var day = newDate.getDay();
if (day > 1 && day < 7) {
i++;
}
}
return newDate;
}
var currentDate = new Date('10/31/2014');
var targetDate = addWeekdays(currentDate, 45);
alert(targetDate);

Using moment.js:
const DATE_FORMAT = 'D-MMM-YYYY';
const SUNDAY = 0; // moment day index
const SATURDAY = 6; // moment day index
const WEEKENDS = [SATURDAY, SUNDAY];
function addBusinessDays(stringDate, numberOfDays, dateFormat = DATE_FORMAT) {
const date = moment(stringDate, dateFormat);
let count = 0;
while (count < numberOfDays) {
date.add(1, 'day');
// Skip weekends
if (WEEKENDS.includes(date.day())) {
continue;
}
// Increment count
count++;
}
return date.format(dateFormat);
}
// Test cases
console.log(addBusinessDays('3-Mar-2021', 1)); // 4-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 2)); // 5-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 3)); // 8-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 4)); // 9-Mar-2021
console.log(addBusinessDays('3-Mar-2021', 5)); // 10-Mar-2021
console.log(addBusinessDays('9-Dec-2011', 13)); // 28-Dec-2011
console.log(addBusinessDays('10-Dec-2011', 13)); // 28-Dec-2011 (Saturday, so remain on Friday)
console.log(addBusinessDays('11-Dec-2011', 13)); // 28-Dec-2011 (Sunday, so remain on Friday)
console.log(addBusinessDays('12-Dec-2011', 13)); // 29-Dec-2011
console.log(addBusinessDays('13-Dec-2011', 13)); // 30-Dec-2011
console.log(addBusinessDays('14-Dec-2011', 13)); // 2-Jan-2012
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>

This question is quite old, but all the previous answers are iterating over the days one by one. That could be inefficient for a large number of days. This works for me, assuming days is a positive int and the startDate is a working day:
function addWorkingDates(startDate, days) {
const current_day = startDate.getDay() - 1; // Week day, starting on Monday
const weekend_days = 2 * parseInt((current_day + days) / 5);
startDate.setDate(changed_to.getDate() + days + weekend_days);
}
addWorkingDates(new Date(),5)

For some reason it was more intuitive to me to try this recursively. This version doesn't account for holidays, but you could change the isValid function to check whatever.
function addWeekdaysToDate(date, numberToAdd) {
var isValid = function(d) { return d.getDay() !== 0 && d.getDay() !== 6 }
if(Math.abs(numberToAdd) > 1) {
return addWeekdaysToDate(
addWeekdaysToDate(date, Math.sign(numberToAdd)),
numberToAdd - Math.sign(numberToAdd)
)
} else if(Math.abs(numberToAdd) === 1) {
var result = new Date(date)
result.setDate(result.getDate() + Math.sign(numberToAdd))
if(isValid(result)) {
return result
} else {
return addWeekdaysToDate(result, Math.sign(numberToAdd))
}
} else if(numberToAdd === 0) {
return date
}
return false
}
console.log(addWeekdaysToDate(new Date(), 1))
console.log(addWeekdaysToDate(new Date(), 5))
console.log(addWeekdaysToDate(new Date(), -7))
In certain browsers you may need a polyfill for Math.sign:
Math.sign = Math.sign || function(x) {
x = +x; // convert to a number
if (x === 0 || isNaN(x)) {
return Number(x);
}
return x > 0 ? 1 : -1;
}

try this solution
<script language="javascript">
function getDateExcludeWeekends(startDay, startMonth, startYear, daysToAdd) {
var sdate = new Date();
var edate = new Date();
var dayMilliseconds = 1000 * 60 * 60 * 24;
sdate.setFullYear(startYear,startMonth,startDay);
edate.setFullYear(startYear,startMonth,startDay+daysToAdd);
var weekendDays = 0;
while (sdate <= edate) {
var day = sdate.getDay()
if (day == 0 || day == 6) {
weekendDays++;
}
sdate = new Date(+sdate + dayMilliseconds);
}
sdate.setFullYear(startYear,startMonth,startDay + weekendDays+daysToAdd);
return sdate;
}
</script>

If you want to get the next working day, from a specific date, use the following code...
function getNextWorkingDay(originalDate) {
var nextWorkingDayFound = false;
var nextWorkingDate = new Date();
var dateCounter = 1;
while (!nextWorkingDayFound) {
nextWorkingDate.setDate(originalDate.getDate() + dateCounter);
dateCounter++;
if (!isDateOnWeekend(nextWorkingDate)) {
nextWorkingDayFound = true;
}
}
return nextWorkingDate;
}
function isDateOnWeekend(date) {
if (date.getDay() === 6 || date.getDay() === 0)
return true;
else
return false;
}

Try this
function calculate() {
var noOfDaysToAdd = 13;
var startDate = "9-DEC-2011";
startDate = new Date(startDate.replace(/-/g, "/"));
var endDate = "";
count = 0;
while (count < noOfDaysToAdd) {
endDate = new Date(startDate.setDate(startDate.getDate() + 1));
if (endDate.getDay() != 0 && endDate.getDay() != 6) {
count++;
}
}
document.getElementById("result").innerHTML = endDate;
}
<div>
Date of book delivery: <span id="result"></span><br /><br />
<input type="button" onclick="calculate();" value="Calculate" />
<br>
<br>
</div>