code: function hasDirectTextDescendantXpath() {
          var selectorResults = ownerDocument.evaluate(axs.properties.TEXT_CONTENT_XPATH,
                                                       element,
                                                       null,
                                                       XPathResult.ANY_TYPE,
                                                       null);
          for (var resultElement = selectorResults.iterateNext();
               resultElement != null;
               resultElement = selectorResults.iterateNext()) {
              if (resultElement !== element)
                  continue;
              return true;
          }
          return false;
      }
docs: Determines whether element has a text node as a direct descendant.
  This method uses XPath on HTML DOM which is not universally supported.
  @return {boolean}