# File lib/html5/html5parser/in_select_phase.rb, line 45
    def endTagOptgroup(name)
      # </optgroup> implicitly closes <option>
      if @tree.open_elements.last.name == 'option' and @tree.open_elements[-2].name == 'optgroup'
        @tree.open_elements.pop
      end
      # It also closes </optgroup>
      if @tree.open_elements.last.name == 'optgroup'
        @tree.open_elements.pop
      # But nothing else
      else
        parse_error("unexpected-end-tag-in-select",
                {"name" => "optgroup"})
      end
    end