@vkc Like I wrote on my wiki:
HTML is a programming language. There, I said it.
It's a programming language because it lets people tell the computer to do cool stuff. In this case, show all kinds of things on screen. That's not much, you say? So what. It's fun. Meaningful. Often even useful.
So, you can't use HTML to perform computation. Big deal. It's been a long time since computers were all, or even mainly, about computation. Deal with it.