These days, it often happens that while I'm reading something in Safari, the webpage suddenly changes to a spam page with "Congratulations! You have won..." I don't even have to click anything, it can happen in the middle of reading. It happens while I'm reading news, mostly it happens on CNN, but also while on other webpages. It only happens on my iPad, not on my Mac or iPhone. Now, if it happened on my Mac, I would suspect a virus. But that shouldn't happen in iOS, right?