And a typical enterprise NIDS would not be able to see beyond those encrypted packet containing JS over 2-way-signed TLS/SSL, or HTTPv3 (QUIC) (or a few other E2E protocols).
Since JavaScript won't be banned (unlike Adobe Flash/ActionScript, BTW Adobe's JavaScript is still being used within PDF files) anytime soon, this is another example of seeing a void and rushing to fill its need for the betterment of Internet citizens.
Just yesterday, another "this is it and how" moment came to me: this Python PDF guy (and a few PDF experts) got me thinking "this is how to remove or make inert the JavaScript inside PDF": https://news.ycombinator.com/item?id=33646951