function popupGenerico(url,ancho,alto,nombre){		
    var ventana;	
    var top = (screen.height/2) - (alto/2);
    var left = (screen.width/2) - (ancho/2);
	ventana=window.open(url, nombre,'width='+ancho+',height='+alto+',scrollbars=0,menubar=0,toolbar=0,location=0,status=0,resizable=0,top='+top+',left='+left,true);
	ventana.focus();
}