// AJAX:
// javascript:Ajax('id_contenedor', 'url_pagina');
// info@albertofortes.com
function Ajax (id_contenedor, url)
{
    var peticion = false;
    if (window.XMLHttpRequest)	{
        peticion = new XMLHttpRequest ();
    } 
	else if (window.ActiveXObject)	{ //si explorer
        try {
            peticion = new ActiveXObject ("Msxml2.XMLHTTP");
        }
        catch (e)   {
            try {
                peticion = new ActiveXObject ("Microsoft.XMLHTTP");
            }
            catch (e) {
            }
        }
    } 
    else
    return false;
    peticion.onreadystatechange = function ()    {
       updater (id_contenedor, peticion);
    }
    peticion.open ('GET', url, true);
    peticion.send (null);
}

function updater (id_contenedor, peticion)
{
    if (peticion.readyState == 4 && (peticion.status == 200 || window.location.href.indexOf ("http") == - 1))
    document.getElementById (id_contenedor).innerHTML = peticion.responseText;
}