code: protected final String renderTagId(HttpServletRequest request, String tagId, AbstractHtmlState state)
      {
          assert(_trs.tagId != null);
          state.id = getIdForTagId(tagId);
          String script = renderDefaultJavaScript(request, state.id);
          return script;
      }
docs: This method will handle creating the tagId attribute.  The tagId attribute indentifies the
  tag in the generated HTML.  There is a lookup table created in JavaScript mapping the <coe>tagId</code>
  to the actual name.  The tagId is also run through the naming service so it can be scoped.  Some tags will
  write that <code>tagid</code> out as the <code>id</code> attribute of the HTML tag being generated.
  @param tagId
  @param state
  @return String