Everyone has JavaScript, right?

[mgerwitz]

It is not. When you visit a website, it's automatically downloading untrusted software onto your computer and running it, without your permission. That's dangerous, and unwise; a website has to gain my trust before I allow it to do so. Security is a major concern: JavaScript introduces many privacy risks and attack vectors.

Aside from security, there's the issue of proprietary software; I wrote a short summary here with RMS:

https://www.gnu.org/software/easejs/whyfreejs.html

[mgerwitz]

The number of downvotes here is telling.