

It might be pretty difficult to implement the work part of proof of work without JS in a practical way. Of the three languages available on the web, HTML, CSS & JS (+ WebAssembly, which requires a bit of JS IIRC & would probably not be available) JS is the only one that allows you to perform the work in a sane way. (It might be possible to use CSS magic with remote resources, but that has its own problems if it’s even possible.)
It would be possible to use a dedicated program or another website to perform the work, but it would be far from seamless to users.
Can confirm.