var date = new Date(2023,0,2); 
var currentThursday = new Date(date.getTime() +(3-((date.getDay()+6) / 7)) * 86400000); 
var yearOfThursday = currentThursday.getFullYear(); 
var firstThursday = new Date(new Date(yearOfThursday,0,4).getTime() +(3-((new Date(yearOfThursday,0,4).getDay()+6) / 7)) * 86400000); 
var weekNumber = Math.floor(1 + 0.5 + (currentThursday.getTime() - firstThursday.getTime()) / 86400000/7);