uBlock Origin[1] is a good idea. Not only does it get rid of potentially harmful ads, it also blocks malware/badware websites. I'd recommend enabling all filter lists under "Malware Domains."

Edit: HTTPS everywhere[2] could also help prevent attackers from redirecting you to their fake "You have a virus!" website.

[1]Chrome: https://chrome.google.com/webstore/detail/ublock-origin/cjpa... Firefox: https://addons.mozilla.org/en-US/firefox/addon/ublock-origin...

[2]https://www.eff.org/https-everywhere