Can not figure out how to save the new outputed document with DOM

With the following script I rename the elements through XSLT of an XML and output the result. However I want to save it in a new file on my browser but the only I managed to do is to save the input XML.

<?php

// create an XSLT processor and load the stylesheet as a DOM 
$xproc = new XsltProcessor();
$xslt = new DomDocument;
$xslt->load('stylesheet.xslt');    // this contains the code from above
$xproc->importStylesheet($xslt);


// your DOM or the source XML (copied from your question)
$xml = '<document><item><title>Hide your heart</title><quantity>1</quantity><price>9.90</price></item></document>';
$dom = new DomDocument;
$dom->loadXML($xml);

// do the transformation
if ($xml_output = $xproc-&开发者_如何学Cgt;transformToXML($dom)) {
    echo $xml_output;
} else {
    trigger_error('Oops, XSLT transformation failed!', E_USER_ERROR);
} 

?>

I used

echo $dom->saveXML();
$dom->save("write.xml")

and replaced it with xml_output with no luck.

if ($xml_output = $xproc->transformToDoc($dom)) {
  $xml_output->save('write.xml');
} else {
  trigger_error('Oops, XSLT transformation failed!', E_USER_ERROR);
}

transformToXML() returns a string instead of a DOMDocument. You can also write the string to a file using the common file handling functions

if ($xml_output = $xproc->transformToXML($dom)) {
  echo $xml_output;
  file_put_contents('write.xml', $xml_output);
} else {
  trigger_error('Oops, XSLT transformation failed!', E_USER_ERROR);
} 

Update: Just found the third method :) Depending on what you want to achieve this is the one you are looking for

$xproc->transformToURI($doc, 'write.xml');

http://php.net/xsltprocessor.transformtouri

You can find the signature of the whole class at the manual: http://php.net/class.xsltprocessor