function popup() {
  var i,p,v,obj,args=popup.arguments;
  
  arrPopups = getElementsByName_iefix('div','div_genres_categorias');
  for(i=0; i<arrPopups.length;i++){
    arrPopups[i].style.visibility = 'hidden';
  }

  for (i=0; i<(args.length-2); i+=3) 
  with (document) 
      if (getElementById && ((obj=getElementById(args[i]))!=null)) { 
        v=args[i+2];
        if (obj.style) { 
            obj=obj.style; 
              //oculto/muestro el combo de paginación para que no moleste
             if(document.getElementById('cmbRegPorPagina')!=null){
                document.getElementById('cmbRegPorPagina').style.display = (v=='mostrar')?'none':'';
             }
            v=(v=='mostrar')?'visible':(v=='ocultar')?'hidden':v; 
        }
        obj.visibility=v; 
      }
}