- var_dump: documentation ( source)
<?php
$xml = <<<'EOX'
<foo>
<bar attr="quux" />
</foo>
EOX;
$dom = new DOMDocument;
$dom->loadXML($xml);
$xp = new DOMXPath($dom);
var_dump($xp->query('//bar/@attr'));
var_dump($xp->query('//bar/@attr')->item(0));