Dynamic Facebook Open Graph tags possible?

Facebook does not parse JavaScript at all, you can´t use dynamic Open Graph tags. It does not really make sense to change them on the fly anyway.

You can only change the OG tags dynamically on the server - obviously. For example: https://yourdomain.com/dynamicogtags.php?title=xxx&description=xxx

<meta property="og:title" content="<?php echo $_GET['title'];?>">

Not sure if that´s what you want to do though, the URL looks pretty ugly that way. Rewrite would be nice, of course.

You also may want to try something like prerender.io, but i am not sure if it will handle dynamic og tags.

As said previously, Facebook doesn't parse JavaScript at all.

One way of doing it (the way I do it) is to use a prerendering service like prerender.io to prerender your pages and redirect requests coming from web crawlers to that prerendering server based on the user-agent (you can easily find how to do that with your Nginx/Apache server on google).

Prerendering services produce an HTML/CSS render of your page, but they wait until the page is fully loaded and the JavaScript is executed before doing so. That way, Facebook gets a render of your website where the JavaScript has been executed and the OpenGraph tags are set correctly!

Prerender is open-source so you can run your own prerender server for free!