code: function getWeekOfMonth(date) {
        var firstDayOfMonth = getFirstDateOfMonth(date);
        return Math.floor((firstDayOfMonth.getDay() + date.getDate() - 1) / 7);
      }
docs: Gets the week of the month that a given date occurs in.
  @param {Date} date
  @returns {number} Index of the week of the month (zero-based).