code: public void setTabindex(int tabindex)
      {
          _state.registerAttribute(AbstractHtmlState.ATTR_GENERAL, HtmlConstants.TABINDEX, Integer.toString(tabindex));
      }
docs: Sets the tabIndex of the rendered html tag.
  @param tabindex the tab index.
  @jsptagref.attributedescription The tabIndex of the rendered HTML tag.  This attribute determines the position of the
  rendered HTML tag in the sequence of tags that the user may advance through by pressing the TAB key.
  @jsptagref.databindable false
  @jsptagref.attributesyntaxvalue <i>string_tabIndex</i>
  @netui:attribute required="false" rtexprvalue="true" type="int"
  description="The tabIndex of the rendered HTML tag.  This attribute determines the position of the
  rendered HTML tag in the sequence of tags that the user may advance through by pressing the TAB key."