// Requiere String.js

//---------------------------------------------
// Valida si los parámetros componen una fecha
//---------------------------------------------

function IsDate(iYear, iMonth, iDay)
{
  iYear = parseInt(iYear, 10);
  if (isNaN(iYear) || iYear < 1900 || iYear > 2100)
    return false;

  iMonth = parseInt(iMonth, 10);
  if (isNaN(iMonth) || iMonth < 1 || iMonth > 12)
    return false;

  var iLastDay = GetDaysInMonth(iYear, iMonth);

  if (isNaN(iDay) || iDay < 1 || iDay > 31)
    return false;

  iDay = parseInt(iDay, 10);
  return (iDay > 0 && iDay <= iLastDay && !isNaN(iDay))
}     
//--------------------
// Formatea una fecha
//--------------------
function FormatDate(iYear, iMonth, iDay, sFormat)
{	
  if (FormatDate.lenght == 3) 
    sFormat = "yyyy-mm-dd";

  if (IsDate(iYear, iMonth, iDay))
    switch (sFormat.toLowerCase())
    {
    case "dd/mm/yyyy":
      return LPad(iDay, 2, "0") + "/" + LPad(iMonth, 2, "0") + "/" + LPad(iYear, 4, "0");
    case "mm/dd/yyyy":
      return LPad(iMonth, 2, "0") + "/" + LPad(iDay, 2, "0") + "/" + LPad(iYear, 4, "0");
    case "mmm-yyyy":
      return MonthName(iMonth) + "-" + LPad(iYear, 4, "0");
    case "yyyy-mm-dd":
      return LPad(iYear, 4, "0") + "-" + LPad(iMonth, 2, "0") + "-" + LPad(iDay, 2, "0");
    }
  return "";
}
//------------------------------------------------
// Obtiene la fecha del día en formato yyyy-mm-dd
//------------------------------------------------
function GetDate()
{
  var dtNow = new Date();
  return dtNow.getFullYear() + "-" + LPad(dtNow.getMonth() + 1, 2, "0") + "-"
       + LPad(dtNow.getDate(), 2, "0");
}
//---------------------------
// Obtiene el nombre del mes
//---------------------------
function MonthName(iMonth)
{
  switch (parseInt(iMonth, 10))
  {
  case 1:
    return "Ene";
  case 2:
    return "Feb";
  case 3:
    return "Mar";
  case 4:
    return "Abr";
  case 5:
    return "May";
  case 6:
    return "Jun";
  case 7:
    return "Jul";
  case 8:
    return "Ago";
  case 9:
    return "Sep";
  case 10:
    return "Oct";
  case 11:
    return "Nov";
  case 12:  
    return "Dic";
  }
  return "";
}
//-----------------------------------
// Obtiene el numero de dias del mes
//-----------------------------------
function GetDaysInMonth(iYear, iMonth)
{
  if (iMonth == 1 || iMonth == 3 || iMonth == 5 || iMonth == 7 ||
      iMonth == 8 || iMonth == 10 || iMonth == 12)
    return 31;
  else if (iMonth == 4 || iMonth == 6 || iMonth == 9 || iMonth == 11)
    return 30;
  else if (iMonth == 2)
    if (IsLeapYear(iYear))
      return 29;
    else
      return 28;
  return 0;
}
//--------------------------------
// Verifica si un año es bisiesto
//--------------------------------
function IsLeapYear(iYear)
{
  if (iYear % 4 == 0 && iYear % 100 != 0 || iYear % 400 == 0)
    return true;
  else
    return false;
}
//--------------------------------
// Valida el rango de las fechas (Controles)
//--------------------------------
function DateRange(yearTo, yearFr, monthTo, monthFr, dayTo, dayFr)
{
	return DateRangePrm(yearTo.value, yearFr.value, monthTo.value, monthFr.value, dayTo.value, dayFr.value);
}

//--------------------------------
// Valida el rango de las fechas (Datos Primitivos)
//--------------------------------
function DateRangePrm(yearTo, yearFr, monthTo, monthFr, dayTo, dayFr)
{
	var frDate = new Date(yearFr, monthFr - 1, dayFr)
	var toDate = new Date(yearTo, monthTo - 1, dayTo)
	return (frDate <= toDate);
}

//--------------------------------
// Valida el rango de las fechas
//--------------------------------
function IsValidDMY(sDate)
{
	var day;
	var month;
	var year;
	var iPos;
	var temp;
	
	iPos = sDate.indexOf("/");
	if(iPos < 0)
		iPos = sDate.indexOf("-");
	if(iPos < 0)
		return false;
		
	day = sDate.substring(0, iPos);
	temp = sDate.substring(iPos + 1)
	iPos = temp.indexOf("/")
	if(iPos < 0)
		iPos = temp.indexOf("-");
		
	if(iPos < 0)
		return false;
		
	month = temp.substring(0, iPos);
	year = temp.substring(iPos + 1);
	if(year.length != 4)
		return false;
	return IsDate(year, month, day);
}
//-------------------------------------------------
// Retorna el día de la semana, siendo domingo = 0
//-------------------------------------------------

function WeekDay(year, month, day)
{
	var _Date = new Date();
	_Date.setDate(day);
	_Date.setMonth(parseInt(month,10)-1);
	_Date.setFullYear(year);
	return _Date.getDay();
}