Why NO scroll bar in Windows for floating img javascripts?

[lagringaloca]

I am primarily a graphic artist (categorization on this tek site made me choose the lesser of all evils when I picked programmer. lol!) anywhoooo- I do webpage design- but I specialize in animations- so I am most certainly LEFT-BRAINED & therefore use a Mac of course! ...and when I first discovered all those wonderful floating, bouncing javascripts to use w/animations on webpages.. . well I was so Haaaaaappy & EXCITED! Only to so RUDELY have to be smashed in the face by the REALITY that on Windows none of those pages have a SCROLL BAR any longer.
I can not find (or recognize) anything to explain this EXTREMELY aggravating phenomenon in the coding. So please, what is up with this¡¡¿¿!!??? ...and can I have floating animations AND a scrollbar in Windows? please say yes, and Thank you... ;-)