Have you really never heard of malware from JavaScript? Buffer overflows and sandbox escapes are almost all JavaScript, still, hasn't changed in the last decade. Sometimes it's a random font parser library or something, but almost always it's JavaScript. And now that browsers are auto-updating and they have fully staffed security teams behind them that get word of a vulnerability being secretly exploited before the general public, most people don't get hit just because they browsed to a random website. But it's still possible, and especially likely that a shady torrent site could be hosting malware or get ""hacked"".

Malicious javascript seeks to bypass security controls. It’s one of the reasons NoScript is a thing. It could be a malware loaded from an ad. Biggest reason for adblockers imo.

Check out this link for learning about this stuff.

https://heimdalsecurity.com/blog/javascript-malware-explained/