protected function appendChild(Node $node) {
    if ($this->tail === NULL) {
      $this->prependChild($node);
    }
    else {
      $this->insertAfterChild($this->tail, $node);
      $this->tail = $node;
    }
    return $this;
  }
protected function appendChild(Node $node) {
    if ($this->tail === NULL) {
      $this->prependChild($node);
    }
    else {
      $this->insertAfterChild($this->tail, $node);
      $this->tail = $node;
    }
    return $this;
  }
protected function appendChild ( Node $ node ) { if ( $ this -> tail === NULL ) { $ this -> prependChild ( $ node ) ; } else { $ this -> insertAfterChild ( $ this -> tail , $ node ) ; $ this -> tail = $ node ; } return $ this ; }
Append a child to node.
@param Node $node
@return $this
Append a child to node .