if (!Sitecore) {
    var Sitecore = new Object();
}

if (!Sitecore.Wfm) {
    Sitecore.Wfm = new Object();
}


Sitecore.Wfm.leapYear = function(year)
{
   Last2Digits = year % 100
   if (Last2Digits == 0)
   {
       flag = year % 400
   }
   else
   {
       flag = year % 4
   }
   
   return flag == 0;     
}

Sitecore.Wfm.getDays = function(month, year) {
  var days = 31;
  switch (month) 
  {
      case 2: days = (Sitecore.Wfm.leapYear(year)) ? 29 : 28;
               break; 
      case 4 :
      case 6 :
      case 9 :
      case 11:
               days = 30;
               break;
  }
  
  return days;
}

Sitecore.Wfm.UpdateDateSelector = function(obj) {
    var fieldItem = Sitecore.Wfm.getAttributeAncestor(obj, Sitecore.Wfm.AttributeKey.FieldIDKey, true);
    var id = fieldItem.id;
    if ($(id + '_month') != null && $(id + '_year') != null) {
        var year = $(id + '_year');
        var month = $(id + '_month');
        var days = Sitecore.Wfm.getDays(parseInt($(id + '_month').selectedIndex + 1, 10), parseInt($(id + '_year', 10).value));
        var selectDays = $(id + '_day');
        if (selectDays != null) {
            while (selectDays.length > days) {
                selectDays.remove(selectDays.length - 1);
            }
            while (selectDays.length < days) {
                var option = document.createElement('option');
                option.text = selectDays.length + 1;
                option.value = selectDays.length + 1;
                try {
                    selectDays.add(option, null);
                }
                catch (ex) {
                    selectDays.add(option);
                }
            }
        }
    }

    Sitecore.Wfm.updateDateComplexValue(obj);
}