JavaScript Calendar Premaker week number

Hi there all, I am a beginner to JavaScript and I need your help guys.

I have here a Calendar Premaker script that makes a basic calendar, what I want to add is a week number right on the left side, I found a ISO Standard (ISO week date - Wikipedia ) that show some rules how it's calculated.

Can anyone help me to implement it?

var sMS = "Ianuarie,Februarie,Martie,Aprilie,Mai,Iunie,Iulie,August,Septembrie,Octombrie,Noiembrie,Decembrie";  
var sDS = "L,Ma,Mi,J,V,S,D";  
var sHS = "1/1,8/3,1/5,25/12";  
  
  
  
  
var pMS = "Scrie numele lunilor (separare prin virgula)\nSau lasa neschimbat!";  
var pDS = "Scrie numele zilelor din saptamana (separare prin virgula)\nSau lasa neschimbat!";  
var pHS = "Scrie sarbatorile, exemplu Z/L[,Z/L,Z/L...]";  
  
  
var AppCap = "Calendar (pt. Adobe Illustrator CC)\n\n";  
var iStr = "Pentru editare elemente:\n\n"+  
   "Window -> Type -> Paragraph Styles\n"+  
   "Window -> Type -> Character Styles\n"+  
   "Window -> Swatches\n\n";  
var pStr = AppCap+"Scrie anul.\nExemplu: 2019";  
  
  
Year = 2019;  
Year = prompt(pStr, Year);   
if(Year>2000 && Year<2100 && Year != null) {  
  
  
MS = prompt(AppCap+pMS, sMS);  
if(MS){  
MC = MS.split(',',12);  
  
for(i=0;i<12;i++) if(MC==null) MC.push(' ');  
for(i=0;i<12;i++) if(MC=='') MC=' ';  
  
DS = prompt(AppCap+pDS, sDS);  
if(DS) {  
DC = DS.split(',',7);  
for(i=0;i<7;i++) if(DC==null) DC.push(' ');  
for(i=0;i<7;i++) if(DC=='') DC=' ';  
  
HS = prompt(AppCap+pHS, sHS);  
if(HS == '') HS = ' ';  
if(HS) {  
HC = HS.split(',');  
HD = Array();  
for(i=0;i<HC.length;i++) {  
  DM = HC.split('/');  
  HD.push(DM[0],DM[1]);  
}  
  
makeCalendar();  
}  
}  
}  
}  
  
  
function makeCalendar() {  
CellHeight = 20;  
CellWidth  = 30;  
  
MN = Array(31,(Year%4==0)?29:28,31,30,31,30,31,31,30,31,30,31);  
FirstDay = Math.floor((Year-2001)*5/4%7);  
FD = FirstDay;  
var DocTop = CellHeight*52;  
var docRef = documents.add(DocumentColorSpace.CMYK,CellWidth*18,DocTop+CellHeight*3);  
  
  
//   
waitRef = docRef.textFrames.add();  
waitRef.contents = "Procesare...\n ©️ PRINTCO";  
waitRef.top = DocTop;  
waitRef.left = 10;  
waitRef.height = 100;  
waitRef.width = 300;  
redraw();  
//  
  
docRef.swatches.removeAll();  
try{docRef.characterStyles.removeAll()} catch(e){}  
  
var nColor = new CMYKColor();  
var nSpotColor = new SpotColor();  
  
var DefaultSpot = docRef.spots.add();  
nColor.cyan = 90;  
nColor.magenta = 60;  
nColor.yellow = 0;  
nColor.black = 0;  
DefaultSpot.name = "Zile";  
DefaultSpot.colorType = ColorModel.PROCESS;  
DefaultSpot.color = nColor;  
  
var HolidaySpot = docRef.spots.add();  
nColor.cyan = 0;  
nColor.magenta = 90;  
nColor.yellow = 60;  
nColor.black = 0;  
HolidaySpot.name = "Sarbatori";  
HolidaySpot.colorType = ColorModel.PROCESS;  
HolidaySpot.color = nColor;  
  
var DaySpot = docRef.spots.add();  
nColor.cyan = 0;  
nColor.magenta = 0;  
nColor.yellow = 0;  
nColor.black = 70;  
DaySpot.name = "Color of caption of week day";  
DaySpot.colorType = ColorModel.PROCESS;  
DaySpot.color = nColor;  
  
var HolydayDaySpot = docRef.spots.add();  
nColor.cyan = 0;  
nColor.magenta = 60;  
nColor.yellow = 20;  
nColor.black = 50;  
HolydayDaySpot.name = "Color of caption of weekend";  
HolydayDaySpot.colorType = ColorModel.PROCESS;  
HolydayDaySpot.color = nColor;  
  
var CaptionSpot = docRef.spots.add();  
nColor.cyan = 0;  
nColor.magenta = 0;  
nColor.yellow = 0;  
nColor.black = 100;  
CaptionSpot.name = "Color of caption of month";  
CaptionSpot.colorType = ColorModel.PROCESS;  
CaptionSpot.color = nColor;  
  
  
var charAttr;  
var paraAttr;  
var DefaultStyle = docRef.characterStyles.add("Week day");  
var HolidayStyle = docRef.characterStyles.add("Holyday");  
var DayCapStyle = docRef.characterStyles.add("Caption of week day");  
var HolydayCapStyle = docRef.characterStyles.add("Caption of weekend");  
var CaptionsStyle = docRef.characterStyles.add("Caption of month");  
  
  
  
  
charAttr = DefaultStyle.characterAttributes;  
//charAttr.size = 14;  
nSpotColor.spot = DefaultSpot;  
charAttr.fillColor = nSpotColor;  
  
charAttr = HolidayStyle.characterAttributes;  
//charAttr.size = 14;  
nSpotColor.spot = HolidaySpot;  
charAttr.fillColor = nSpotColor;  
  
charAttr = DayCapStyle.characterAttributes;  
//charAttr.size = 14;  
nSpotColor.spot = DaySpot;  
charAttr.fillColor = nSpotColor;  
  
charAttr = HolydayCapStyle.characterAttributes;  
//charAttr.size = 14;  
nSpotColor.spot = HolydayDaySpot;  
charAttr.fillColor = nSpotColor;  
  
charAttr = CaptionsStyle.characterAttributes;  
//charAttr.size = 14;  
nSpotColor.spot = CaptionSpot;  
charAttr.fillColor = nSpotColor;  
  
  
var paraDayStyle = docRef.paragraphStyles.add("Dates");  
paraAttr = paraDayStyle.paragraphAttributes;  
paraAttr.justification = Justification.RIGHT;  
  
var paraWeekDayStyle = docRef.paragraphStyles.add("Days of week");  
paraAttr = paraWeekDayStyle.paragraphAttributes;  
paraAttr.justification = Justification.RIGHT;  
  
var paraMonthStyle = docRef.paragraphStyles.add("Months");  
paraAttr = paraMonthStyle.paragraphAttributes;  
paraAttr.justification = Justification.LEFT;  
  
  
  
LeftMargin = CellWidth;  
for(m=0; m<6; m++){  
textRef = docRef.textFrames.add();  
textRef.contents = MC;  
textRef.top = DocTop - m*9*CellHeight+CellHeight*2;  
textRef.left = CellWidth + LeftMargin;       
CaptionsStyle.applyTo(textRef.textRange)  
paraMonthStyle.applyTo(textRef.paragraphs[0], true);  
  
for(i=0; i<7; i++){  
textRef = docRef.textFrames.add();  
textRef.contents = DC;  
textRef.top = DocTop - m*9*CellHeight+CellHeight;  
textRef.left = i*CellWidth + LeftMargin;  
(i<5) ? DayCapStyle.applyTo(textRef.textRange) : HolydayCapStyle.applyTo(textRef.textRange);  
paraWeekDayStyle.applyTo(textRef.paragraphs[0], true);  
}   
for(d=0; d<MN; d++){  
textRef = docRef.textFrames.add();  
textRef.contents = d+1;  
textRef.top = DocTop - ((Math.floor((FD+d)/7)*CellHeight) + m*9*CellHeight);  
textRef.left = (FD+d)%7*CellWidth + LeftMargin;  
paraDayStyle.applyTo(textRef.paragraphs[0], true);  
if ((FD+d+1)%7) DefaultStyle.applyTo(textRef.textRange);  
else            HolidayStyle.applyTo(textRef.textRange);  
if (isHoliday(d+1,m+1)) HolidayStyle.applyTo(textRef.textRange);  
}  
FD = (FD+d)%7;  
}  
  
LeftMargin = CellWidth*9;  
for(m=6; m<12; m++){  
textRef = docRef.textFrames.add();  
textRef.contents = MC;  
textRef.top = DocTop - (m-6)*9*CellHeight+CellHeight*2;  
textRef.left = CellWidth + LeftMargin;       
CaptionsStyle.applyTo(textRef.textRange)  
paraMonthStyle.applyTo(textRef.paragraphs[0], true);  
  
for(i=0; i<7; i++){  
textRef = docRef.textFrames.add();  
textRef.contents = DC;  
textRef.top = DocTop - (m-6)*9*CellHeight+CellHeight;  
textRef.left = i*CellWidth + LeftMargin;       
(i<5) ? DayCapStyle.applyTo(textRef.textRange) : HolydayCapStyle.applyTo(textRef.textRange);  
paraWeekDayStyle.applyTo(textRef.paragraphs[0], true);  
}   
for(d=0; d<MN; d++){  
textRef = docRef.textFrames.add();  
textRef.contents = d+1;  
textRef.top = DocTop - ((Math.floor((FD+d)/7)*CellHeight) + (m-6)*9*CellHeight);  
textRef.left = (FD+d)%7*CellWidth + LeftMargin;  
paraDayStyle.applyTo(textRef.paragraphs[0], true);  
if ((FD+d+1)%7) DefaultStyle.applyTo(textRef.textRange);  
else            HolidayStyle.applyTo(textRef.textRange);  
if (isHoliday(d+1,m+1)) HolidayStyle.applyTo(textRef.textRange);  
}  
FD = (FD+d)%7;  
}  
  
waitRef.remove();  
redraw();  
  
alert(iStr);  
}  
  
  
function isHoliday(day,month)  
{  
var i;  
for(i=0; i<HD.length; i+=2){  
if(day==HD && month==HD[i+1]) return true;  
}  
return false;  
}