in src/Facebook/InstantArticles/Elements/Audio.php [188:219]
public function toDOMElement($document = null)
{
if (!$document) {
$document = new \DOMDocument();
}
$element = $document->createElement('audio');
// title markup optional
if ($this->title) {
$element->setAttribute('title', $this->title);
}
// Autoplay mode markup optional
if ($this->autoplay) {
$element->setAttribute('autoplay', 'autoplay');
}
// Autoplay mode markup optional
if ($this->muted) {
$element->setAttribute('muted', 'muted');
}
// Audio URL markup. REQUIRED
if ($this->url) {
$source_element = $document->createElement('source');
$source_element->setAttribute('src', $this->url);
$element->appendChild($source_element);
}
return $element;
}