Enable vertical scrollbars in Firefox permanently with CSS2

Sometimes we build websites with both long and short pages. Some of them dont need scrollbars and browsers dont display scrollbars as default. But if you have centered container Firefox change tha x-place(margin to left) depends on scrollbars. It looks like design/position problem. To prevent this we need permanent enabled scrollbars but not horizontally. We can enable xy scrollbars with "body { overflow: scroll; }". There is no property for just y in css2. In css3 there are properties like overflow-y, overflow-x etc. Use following code to fix it:

html { height: 101%; }