DEFER or ASYNC allowed on a stylesheet include?
You could do this:
<link rel="stylesheet" href="/css/style.css" media="none" onload="if(media!=='all')media='all'" >
and create a noscript fallback
Defer
and Async
are specific attributes of the tag <script>
https://developer.mozilla.org/en/docs/Web/HTML/Element/script
They will not work in other tags, because they don't exist there. A stylesheet is not a script that contains logic to be executed in parallel or after the loading. A stylesheet is a list of static styles that get applied atomically to html.