php中操作xml，关于encoding..

Question

$dom = new DOMDocument("1.0"); $info = $dom->createElement("ourinfo");
$dom->appendChild($info);$auth = $dom->createElement("ourauth");
$info->appendChild($auth);
$text_auth = $dom->createTextNode("xml_encoding"); 
$auth ->appendChild($text_auth);echo $dom->saveXML();----------得到结查
<?xml version="1.0" ?> 
<ourinfo>
  <ouruth>xml_encoding</ourauth>
</ourinfo>请问如何在 <?xml version="1.0" ?> 内加 encoding="UTF-8"

Answer 1

$dom->encoding = "UTF-8";