It doesn’t work alone.

This is overflow: hidden; on body:

• JsFiddle Link (doesn’t work)

This is overflow: hidden; on html:

• JsFiddle Link (works)
• note that only setting overflow: hidden; on html tag won’t work either. It has to be on both html tag and body tag. And the one “hidden” that works would be the one set upon body.

It seems that the width and height of body could only be controlled through html tag.