PC Tech Thread

Sorry to be a klutz, but could someone put this into real layman's terms what the problem is, what it will do, and how best to guard against it. So I can, um, explain it better to my mum....

Think about that for a bit. Just by visiting a webpage with some dodgy
JavaScript on it, it could suck out private information held in the
browser (such as passwords and logins for other sites) and then
exfiltrate them.

Does this mean that as I don't store any passwords on my browser anyway, and wipe browser history daily, that I'm a little bit less vunerable...?