When I am on the web to consume information, JS is not required. It can be useful for some data visualization but that's it. This is, of course, not the approach taken by almost all web pages. (Even if you insist on collapsible navigation which is dubious at best, you still don't need JS, CSS is enough. https://codepen.io/raubaca/pen/PZzpVe )

In general, it is a mighty odd notion every random person who can throw up a web page gets to run code on my machine. This shouldn't be a casual thing, sandbox or not.