Stupid javascript box keeps popping up.

I apologize if this is the wrong place for this. The other day my sister was on my computer (Macbook pro) and went to this stupid website to calculate her BMR. Apparently at this site a box popped up asking for information (age, height, weight etc...) Well over 24 hours later after leaving the site the little survey boxes keep popping up. I've tried restarting the computer, cleaning out cookies and cache then to just fully reseting safari and still a box with javascript written at the top pops up saying "enter your sex using lower case m or f in the box below." I'm not computer savvy so I don't know what to do to make it stop. Is this some kind of virus or spyware? I also wanted to add that I already have it set to block popups.