- var_dump: documentation ( source)
<?php
$doc = new DOMDocument('1.0', 'utf-8');
$rss = $doc->appendChild($doc->createElement('rss'));
$channel = $rss->appendChild($doc->createElement('channel'));
$channel->setAttribute('xmlns:g', 'http://foo.com/foo/bar/baz');
$item = $channel->appendChild($doc->createElement('item'));
$foo = $item->appendChild($doc->createElement('g:foo'));
$foo->appendChild($doc->createTextNode('bar'));
echo $doc->saveXML() . "\n";
$xpath = new DOMXPath($doc);
var_dump($xpath->query('/rss/channel')->item(0));