Says the person posting to a web application. Where exactly do you want to draw the line?
Hacker News has no need for JavaScript
JavaScript makes the upvote/downvote buttons work in a way that users expect them to work. Given that is almost 50% of the end-user functionality of this site, I'd say that's pretty important.
This website is the perfect example that a web app can be extremely functional without requiring Javascript, especially not for doing CSS and markup.