protected function getNodePropertyByTagName(\DOMElement $node, $tagName, $propertyName)
{
$values = array();
$results = $node->getElementsByTagName($tagName);
if ($results->length) {
foreach ($results as $result) {
if ($result->getAttribute($propertyName)) {
$values[] = $result->getAttribute($propertyName);
}
}
}
return $values;
}