PHP操作xml

/*获取图片新闻列表*/
function getPicNews($number=5){
    require_once 'include/content_class.php';
    $Content=new Content();
    $sql='select contentid as id,title,pic,typeid from `cms_content` where pic<>"" order by input_time desc';
    $rows=$Content->getRowsBySQL($sql,$number);
    $dom=new DOMDocument('1.0','GBK');
    $root=$dom->createElement('slider');
    $dom->appendChild($root);
    foreach($rows as $val){
      $item=$dom->createElement('item');
      $root->appendChild($item);
     
      $title=$dom->createAttribute('title');
      $title_text=$dom->createTextNode($val['title']);
      $title->appendChild($title_text);
      $item->appendChild($title);

      $href=$dom->createAttribute('href');
      $href_text=$dom->createTextNode('show.php?newsid='.$val['id'].'&classid='.$val['typeid']);
      $href->appendChild($href_text);
      $item->appendChild($href);

      $imageurl=$dom->createAttribute('imageurl');
      $imageurl_text=$dom->createTextNode($val['pic']);
      $imageurl->appendChild($imageurl_text);
      $item->appendChild($imageurl);
    }
    return $dom->saveXML();
}