var aData, bData;
aData = new Array (12);
aData = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

function VerificaBisexto(obj)
{
	var bisexto, ano;
	ano = obj.value;
	
	if ((ano % 4) == 0) 
	{
		if ((ano % 100) == 0 && (ano % 400) != 0)
			return false;
		else
			return true;
	} 
	else
		return false;
}

function ChangeDay(obj1, obj2, obj3)
{
	var NrDias = 0, n = 0, i = 0, p = 1;
	var oldIndex;
	
	oldIndex = obj1.selectedIndex;
	obj1.options.length = 1;
	
	if(obj2.value == 2)
	{
		if(VerificaBisexto(obj3))
			NrDias = 29;
		else
			NrDias = 28;
	}
	else
		NrDias = aData[obj2.value - 1];
	
	for ( i = 1 ; i <= NrDias; i++)
	{
		obj1.options.length = p;
		obj1.options[p-1].value = i;
		obj1.options[p-1].text = i;
		p++;
	}
	
	
	if(oldIndex != -1)
	{
		if(oldIndex >= (obj1.options.length -1))
			obj1.options.selectedIndex = obj1.options.length - 1;
		else
			obj1.options.selectedIndex = oldIndex;
			
	}
	
	
	
}