Check for innerXXX before clientXXX
Check for innerXXX before clientXXX

innerWidth/Height is the correct way to get the viewport.

On IE6/7/8 it does not work so we take the clientWidth/Height.

It seems that getting the viewport correctly on safari mobile is a
complete mess, not yet handled.

fasterize/in-viewport,tzi/in-viewport,ipy/in-viewport,vvo/in-viewport,fasterize/in-viewport,tzi/in-viewport,vvo/in-viewport,ipy/in-viewport