function DateChange(MonthDropDown, DayDropDown, YearDropDown) 
{
//    var MonthDropDown = document.getElementById('PickMonth');
//    var DayDropDown = document.getElementById('PickDay');
//    var YearDropDown = document.getElementById('PickYear');
    
    if (MonthDropDown === null) { return; }
    if (DayDropDown === null) { return; }
    if (YearDropDown === null) { return; }
    
    var selMonthIndex = MonthDropDown.selectedIndex;
    var selYearIndex = YearDropDown.selectedIndex;
    var has29 = -1;
    var has30 = -1;
    var has31 = -1;
    var selYearValue = YearDropDown.options[selYearIndex].value;
    
    
    var leapYear;
    if (selYearValue % 100 === 0)
    {
        if (selYearValue % 400 === 0)
            { leapYear = 1; }
        else
            { leapYear = 0; }
    }
    else if (selYearValue % 4 === 0)
        { leapYear = 1; }
    else
        { leapYear = 0; }
        
    // window.alert('Got here ' + selYearValue + " leap: " +  leapYear);

    //has this item
    for(var j = 0; j < DayDropDown.options.length; j++)
    {	//for
        if (DayDropDown.options[j].value >= 28)
        {
            if (DayDropDown.options[j].value == 29) { has29 = j; }	//if
            if (DayDropDown.options[j].value == 30) { has30 = j; }	//if
            if (DayDropDown.options[j].value == 31) { has31 = j; }	//if
        }
    }	//for

    // 30 day month
    if ((selMonthIndex == 3) || (selMonthIndex == 5) ||
        (selMonthIndex == 8) || (selMonthIndex == 10))
    {	//if

        if (has31 != -1) {
            DayDropDown.removeChild(DayDropDown.options[has31]);
        }

        if (has29 == -1) {
            var option29 = document.createElement('OPTION');
            option29.innerHTML = '29';
            option29.value = '29';
            DayDropDown.appendChild(option29);
        }

        if (has30 == -1) {
            var option30 = document.createElement('OPTION');
            option30.innerHTML = '30';
            option30.value = '30';
            DayDropDown.appendChild(option30);
        }
    }	//if

    // February
    else if (selMonthIndex == 1) 
    {	//else if
        if (has31 != -1) {
            DayDropDown.removeChild(DayDropDown.options[has31]);
        }

        if (has30 != -1) {
            DayDropDown.removeChild(DayDropDown.options[has30]);
        }

        if (leapYear == 1)
        {
            if (has29 == -1) {
                var optionFeb29 = document.createElement('OPTION');
                optionFeb29.innerHTML = '29';
                optionFeb29.value = '29';
                DayDropDown.appendChild(optionFeb29);
            }	
        }
        else {
            if (has29 != -1){
                DayDropDown.removeChild(DayDropDown.options[has29]);
            }
        }
        
    }

    // 31 day month
    else {

        if (has29 == -1){
            var option29 = document.createElement('OPTION');
            option29.innerHTML = '29';
            option29.value = '29';
            DayDropDown.appendChild(option29);
        }

        if (has30==-1){
            var option30 = document.createElement('OPTION');
            option30.innerHTML = '30';
            option30.value = '30';
            DayDropDown.appendChild(option30);
        }

        if (has31==-1){
            var option31 = document.createElement('OPTION');
            option31.innerHTML = '31';
            option31.value = '31';
            DayDropDown.appendChild(option31);
        }
    }	

    //var daySelectedTextBox = document.getElementById('daySelectedTextBox');
    //daySelectedTextBox.value = DayDropDown.options[DayDropDown.selectedIndex].value;

}	//function