if params[:value] == Result::MARKING_STATES[:complete] && @result.marks.find_by_mark(nil)
      render :update do |page|
        page.show 'criterion_incomplete_error'
      end
    else # Hide message (if any) and then continue as normal.
      render :update do |page|
        page.hide 'criterion_incomplete_error'
      end


replaced with


    if params[:value] == Result::MARKING_STATES[:complete] && @result.marks.find_by_mark(nil)
      render :action => "show_criteria_error"
    else # Hide message (if any) and then continue as normal.
      render :action => "hide_criteria_error"