Virus warning on my iPhone after clicking a website

I clicked on an average looking website and got a popup (I assume) that I’ve gotten before on a completely different website. I got pretty scared so I closed out quickly but it basically said virus detected and I think had a button leading me somewhere. It was green but after researching other virus warnings it looks like none of them. Is it real? All I did was click on a website from google search, nothing else. Is my phone safe?

[Re-Titled by Moderator]