code: public Input addButton(String tag,
                             String label)
      {
          if (buttons==null)
              buttonsAtBottom();
          Input e = new Input(Input.Submit,tag,label);
  
          if (extendRow)
              addField(null,e);
          else
              buttons.add(e);
          return e;
      }
docs: Add a Submit Button.
  @param tag The form name of the element
  @param label The label for the Button