function nuevoAjax(){
    var xmlhttp=false;
    try {
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
        try {
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (E) {
            xmlhttp = false;
        }
    }
    if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
        xmlhttp = new XMLHttpRequest();
    }
    return xmlhttp;
}

function recibeid(_pagina,valorget){
    var ajax=nuevoAjax();
    ajax.open("GET", _pagina+"?"+valorget,false);
    ajax.send(null);
    var ret= ajax.responseText;
    return ret;
}