- var_dump: documentation ( source)
<?php
$html = <<<EOF
<div>
<a href="#">1</a>
<a href="test">2</a>
</div>
EOF;
$doc = new DOMDocument();
$doc->loadHTML($html);
$selector = new DOMXPath($doc);
foreach($selector->query("//a/@href[.='#']") as $node) {
var_dump($node->nodeValue);
}