//  Ajax
function crearObjetoAjax()
{
    var ajax = false;
    if (window.XMLHttpRequest){
        ajax = new XMLHttpRequest();
    } else if(window.ActiveXObject){
        ajax = new ActiveXObject("Microsoft.XMLHTTP");
    }
    return ajax;
}

function obtenerDatos(objAjax, url)
{
    objAjax.open("GET", url, false); // Sincrónica
    objAjax.send(null);
    if(objAjax.readyState == 4 && objAjax.status == 200){
        return objAjax.responseText;
    }
}

function escribirHTML(div, html)
{
    document.getElementById(div).innerHTML = html;
}

function abrirURL (url)
{
    window.open("url.php?" + url);
}