code: function(node, nsuri, name, def) {
          var value;
          var eles = this.getElementsByTagNameNS(node, nsuri, name);
          if(eles && eles[0] && eles[0].firstChild
              && eles[0].firstChild.nodeValue) {
              value = this.getChildValue(eles[0]);
          } else {
              value = (def == undefined) ? "" : def;
          }
          return value;
      }
docs: Method: _getChildValue
  
  Parameters:
  node - {DOMElement}
  nsuri - {String} Child node namespace uri ("*" for any).
  name - {String} Child node name.
  def - {String} Optional string default to return if no child found.
  
  Returns:
  {String} The value of the first child with the given tag name.  Returns
  default value or empty string if none found.