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 cargaXML(url,id){
        var capa;
        capa = document.getElementById(id);
        ajax=NuevoAjax(); 
        ajax.open("GET", url,true); 
        ajax.onreadystatechange=function(){
                if(ajax.readyState==1){
                        capa.innerHTML = "<div align='center'><img src='tema/ajax-loaderb.gif'></div>";
                }else if(ajax.readyState==4){
                        if(ajax.status==200){
                                capa.innerHTML = ajax.responseText;
                        }else if(ajax.status==404){
                                capa.innerHTML = "La página no existe";
                        }else{
                                capa.innerHTML = "Error:".ajax.status; 
                        }
                }
        }
        ajax.send(null);
}