On my iPhone 8, when on the internet, I get the same pop up every so often that shows I won something. If I close it, it brings up a fake amazon page. My old 4s did the same thing. Only turning off JavaScript stopped it.
I’ve cleared history and cookies. Is there anything else I can do to prevent them? No, I’m not looking at pron. I have to close the page and open a new one to get back where I was.