// magic javascript to add additional empty selectors
      // when last one is filled by user.
      // only tested with a ComboBox itemRenderer
      
      set needsJQuery;
      int n = l(list)+1;
      out.add(hjs("var \*name*/_n = " + n + ";"));
      for i to n:
        out.add(renderInput(name + "_" + i, r.itemRenderer, _get(list, i)));
      out.add(hjs("\*name*/_\*n-1*/"));