Website scrolls acting weird
 

sometimes when I go to a site, The website scroll up and down on its own really fast so I can't read anything and what not. What causes this?

Evil elves.

Do you see the double arrow thing you see when you hit the middle button/scroll wheel? You could be click that by mistake.

Also, make sure nothing is touching the spacebar, because that happens to me a lot. I'll have my hand on it and not realize it when my browser scrolls.

If those aren't it, scan for adware, spyware, viruses, etc.