function ComuteFields(id_front, id)
{
	HideId(id_front);
	ShowId(id);
	var obj = document.getElementById(id);
	if (obj) obj.focus();
}
function ComuteFields2(id_front, id)
{
	var obj = document.getElementById(id);
	var obj_front = document.getElementById(id_front);
	if (obj.value=="")
	{
		HideId(id);
		ShowId(id_front);
	}
}