Does a popup saying I'm infected mean I've been hacked?

Episode 1457 (2:17:49)

Jay from Long Beach, CA
uBlock Origin

Jay keeps getting a popup when surfing that says he's been infected with a virus. Should he be worried? Leo says no. Chances are, it's the website that has been hacked, and a piece of javascript has been put into that site. If he closes out the website, it simply goes away. It may also end up being some sort of extension that got installed in his browser. Jay should clear out all his extensions and it should solve it. Then Leo recommends installing a plugin called uBlock Origin. That will keep them from popping up.