// Used by validator
function DateTimePickerEvaluateIsValid(val)
{
    var ddlDay = document.getElementById(val.controltovalidate + '_ddlDay');
    var ddlMonth = document.getElementById(val.controltovalidate + '_ddlMonth');
    var txtYear = document.getElementById(val.controltovalidate + '_txtYear');
    
    var isEverythingEmpty = ddlDay.selectedIndex == 0 && ddlMonth.selectedIndex == 0 && txtYear.value == '';
    var isSomeoneNotEmpty = ddlDay.selectedIndex != 0 || ddlMonth.selectedIndex != 0 || txtYear.value != '';
    
    if (isEverythingEmpty && !isSomeoneNotEmpty)
    {
        return (val.includeempty == "True")
    }
    
    var day = parseInt(ddlDay.options[ddlDay.selectedIndex].value, 10);
    var month = parseInt(ddlMonth.options[ddlMonth.selectedIndex].value, 10) - 1;
    var year = parseInt(txtYear.value, 10);
    
    var dayobj = new Date(year, month, day);
    return (dayobj.getMonth() == month) && (dayobj.getDate() == day) && (dayobj.getFullYear() == year);
}