function  Abrir_ventana (ventana,ancho,alto,ptop,pleft) {
var opciones= "directories = no,status = no,toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, width=" + ancho+", height="+alto+", top="+ptop+", left="+pleft;
window.open(ventana,"",opciones);
return false;
}