Get week of the month

Question

How can i get the week number of month using javascript / jquery?

For ex.:

First Week: 5th July, 2010. / Week Number = First monday

Answer 1

Having struggle with this topic too - thanks to Olson.dev! I've shortened his function a little bit, if somebody is interessted:

// returns week of the month starting with 0
Date.prototype.getWeekOfMonth = function() {
  var firstWeekday = new Date(this.getFullYear(), this.getMonth(), 1).getDay();
  var offsetDate = this.getDate() + firstWeekday - 1;
  return Math.floor(offsetDate / 7);
}

update: if you need a localized version - you have to tweak the firstWeekday variable

// german version - week starts with monday
Date.prototype.getWeekOfMonth = function() {
  var firstWeekday = new Date(this.getFullYear(), this.getMonth(), 1).getDay() - 1;
  if (firstWeekday < 0) firstWeekday = 6;
  var offsetDate = this.getDate() + firstWeekday - 1;
  return Math.floor(offsetDate / 7);
}