code: function(node, nsuri, name, def) {
          var value;
          var nodes = this.getElementsByTagNameNS(node, nsuri, name);
          if (nodes && nodes.length > 0) {
              value = this.getChildValue(nodes[0], def);
          } else {
              value = def;
          }
          return value;
      }
docs: Method: getFirstChildValue
  
  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.