function DatePickerClient(id, dayDropDownId, monthDropDownId, calendarPopupId, childDatePickerId, onClientChange, minimumChildIncrement)
{
   /** -- PROPERTIES -- **/
   
   this.Id = id;
   this.DayDropDownId = dayDropDownId;
   this.MonthDropDownId = monthDropDownId;
   this.CalendarPopupId = calendarPopupId;
   this.ChildDatePickerId = childDatePickerId;
   this.OnClientChange = onClientChange;
   this.MinimumChildIncrement = minimumChildIncrement;
      
   
   /** -- METHODS -- **/
   
   if (typeof DatePickerClient._initialised == "undefined")
   {      
      // SetDate (return: Void)
      DatePickerClient.prototype.SetDate = function(dNewDate)
      {
         this.SetDropDownDate(dNewDate);
         this.SetCalendarDate(dNewDate);
      }
      
      // GetDropDownDate (return: Date)
      DatePickerClient.prototype.GetDropDownDate = function()
      {
         var oDayDropDown = document.getElementById(this.DayDropDownId);
         var oMonthDropDown = document.getElementById(this.MonthDropDownId);
         
         var aMonthYear = oMonthDropDown.options[oMonthDropDown.selectedIndex].value.split("|");
         
         var iSelectedDay = parseInt(oDayDropDown.options[oDayDropDown.selectedIndex].value);
         var iSelectedMonth = parseInt(aMonthYear[0]);
         var iSelectedYear = parseInt(aMonthYear[1]);
         
         var aDaysInMonth = getDaysInMonth(iSelectedYear);
         
         if (iSelectedDay > aDaysInMonth[iSelectedMonth])
         {
            // Raise status msg?
            
            // Change selected date to last day of selected Month
            iSelectedDay = aDaysInMonth[iSelectedMonth];
            oDayDropDown.selectedIndex = aDaysInMonth[iSelectedMonth] - 1;
         }
         
         return new Date(iSelectedYear, iSelectedMonth, iSelectedDay, 0, 0, 0);
      }
      
      // GetCalendarDate (return: Date)
      DatePickerClient.prototype.GetCalendarDate = function()
      {
         return CalendarPopup_FindCalendar(this.CalendarPopupId).GetDate();
      }
      
      // SetDropDownDate (return: Void)
      DatePickerClient.prototype.SetDropDownDate = function(dNewDate)
      {
         var oDayDropDown = document.getElementById(this.DayDropDownId);
         var oMonthDropDown = document.getElementById(this.MonthDropDownId);
         
         var dCurrentDate = new Date();
         
         var iNewDay = dNewDate.getDate();
         var iNewMonth = dNewDate.getMonth();
         var newSelectedIndex = 0;
         
         if (dNewDate.getMonth() != dCurrentDate.getMonth() || dNewDate.getFullYear() != dCurrentDate.getFullYear())
         {
            //Need to select next years current month.
            var aIndex = new Array();
         
            var iIndex = 0;
            
            // Calculate Index Pos for each month
            // Based on the assumption:
            //  - The current Month will always be in pos 0
            //  - The current Month + 1 Year will always be in pos 12
            
            // Calc positions for months remaining this year
            for (var i = dCurrentDate.getMonth(); i < 12; i++)
            {
               aIndex[i] = iIndex;
               iIndex++;
            }
            
            // Calc positions for applicable months next year
            for (var i = 0; i < 12 - (12 - dCurrentDate.getMonth()) + 1; i++)
            {
               aIndex[i] = iIndex;
               iIndex++;
            }
            
            newSelectedIndex = aIndex[dNewDate.getMonth()];
         }
         
         oDayDropDown.selectedIndex = iNewDay - 1;
         oMonthDropDown.selectedIndex = newSelectedIndex;
      }
      
      // SetCalendarDate (return: Void)
      DatePickerClient.prototype.SetCalendarDate = function(dNewDate)
      {
         CalendarPopup_FindCalendar(this.CalendarPopupId).SelectDate(dNewDate);
      }
      
      // UpdateChildDatePicker (return: Void)
      DatePickerClient.prototype.UpdateChildDatePicker = function(dNewDate)
      {
         if (this.ChildDatePickerId.length > 0)  // check null etc
         {
            oChildDatePicker = findDatePickerClient(this.ChildDatePickerId);
            
            if (oChildDatePicker.GetDropDownDate() < dNewDate)
            {
               var iNewDay = dNewDate.getDate();
               var iNewMonth = dNewDate.getMonth();
               var iNewYear = dNewDate.getFullYear();
               var aDaysInMonth = getDaysInMonth(iNewYear);

               var iChildDay = iNewDay + parseInt(this.MinimumChildIncrement);
                    
               var iChildMonth = iNewMonth;
               
               if (iChildDay > aDaysInMonth[iChildMonth])
               {
                  iChildMonth++;
                  iChildDay = iChildDay - aDaysInMonth[iNewMonth];
               }
               
               var dChildDate = new Date(iNewYear, iChildMonth, iChildDay);
               
               oChildDatePicker.SetDate(dChildDate);
            }
         }
      }

      // CallClientFunction (return: Void)
      DatePickerClient.prototype.CallClientFunction = function()
      {
         if (this.OnClientChange.length > 0)
         {
            eval(this.OnClientChange + "();");
         }
      }

      /** -- EVENTS -- **/
      
      // DropDownDateChanged (return: Void)
      DatePickerClient.prototype.DropDownDateChanged = function()
      {         
         var _dDropDownDate = this.GetDropDownDate();
         var _dCalendarDate = this.GetCalendarDate();
         
         if (_dDropDownDate.toUTCString() !== _dCalendarDate.toUTCString())
         {
            this.SetCalendarDate(_dDropDownDate);
            this.UpdateChildDatePicker(_dDropDownDate);
            this.CallClientFunction();
         }
      }
      
      // CalendarPopupDateChanged (return: Void)
      DatePickerClient.prototype.CalendarPopupDateChanged = function()
      {         
         var _dDropDownDate = this.GetDropDownDate();
         var _dCalendarDate = this.GetCalendarDate();
         
         if (_dCalendarDate.toUTCString() !== _dDropDownDate.toUTCString())
         {
            this.SetDropDownDate(_dCalendarDate);
            this.UpdateChildDatePicker(_dCalendarDate);
            this.CallClientFunction();
         }
      }
   }
   
   
   /** -- INITILISATION FLAG -- **/
   DatePickerClient._initialised = true;
}


/** -- STAND ALONE METHODS -- **/

function findDatePickerClient(id)
{
   for (var i = 0; i < aMyTestArray.length; i++)
   {
      if (aMyTestArray[i].Id == id)
      {
         return aMyTestArray[i];
      }
   }
}

function getDaysInMonth(iYear)
{
   var _aDaysInMonth = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);

   // check for leap year
   if ( ( (iYear % 4 == 0) && (iYear % 100 != 0) ) || (iYear % 400 == 0) )
   {
      _aDaysInMonth[1] = "29";
   }
   
   return _aDaysInMonth;
}


/** -- EVENT HANDLERS -- **/

function onDropDownValueChange(id)
{
   findDatePickerClient(id).DropDownDateChanged();
}

function onCalendarPopupValueChanged(id)
{
   findDatePickerClient(id).CalendarPopupDateChanged();
}