PHP DOMElement使用php shorttag获取属性值

Question

I have a document in phtml that has this tag:

<meta name="description" content="<?= getenv("LANDING_DESCRIPTION") ?>">

And i want to use the DOMDocument() library to read the content attribute of that, but i believe that is because php shorttag echo, i get only <?= getenv has value of content attribute.

Any clue ?

Thanks