// Autor: Moisés Carrasco <moises4879@gmail.com>
// Ultima actualización: 12/12/2005


function trim(cadena)
{
	var i;
	var cad2
	for(i=0;i<cadena.length;i++)
	{
		if(cadena.charAt(i) != " ")
			break;
	}
	cad2 = cadena.substring(i,cadena.length);
	for(i=cad2.length-1;i>=0;i--)
	{
		if(cad2.charAt(i) != ' ')
			break;
	}
	if(i<cad2.length-1)
		cad2 = cad2.substring(0,i+1);
	return cad2;
}

function vacio(obj,msg)
{
	if(!(/\S/.test(obj.value))) { if(msg != "") { alert(msg); } obj.focus(); return true; }
	else return false;
}


function item_select(objselect,valor)
{
	if(objselect.options.length == 0) return;
	objselect.value = valor;
	if(objselect.selectedIndex == -1)
		objselect.selectedIndex = 0;
}

function n_inst(obj)
{
	if(obj.length != null)
	{
		return obj.length;
	}
	else
		if(obj != null)
			return 1;
		else
			return 0;
}