N30

            var subcats = cats[foo_barcat_id].subcats;

	    var subcatHash = new Hash(subcats);

	    $$('tr[id^=all_fields_]').each(function(el) { if(el.id == 'all_fields_'+foo_barcat_id) { el.style.display = ''; } else { el.style.display = 'none'; }});

	    if(foo_barcat_id == 0 || subcatHash.getValues().length == 0) {

	      $('foo_barsubcat_id').options.length = 1;