Fix scrolling code.
Fix scrolling code.

window.onscroll doesn't seem to actually trigger an event with
pageX and pageY properties.  However, document.scrollElement.scrollLeft
and document.scrollElement.scrollTop do work.

google/codeworld,google/codeworld,alphalambda/codeworld,pranjaltale16/codeworld,pranjaltale16/codeworld,alphalambda/codeworld,pranjaltale16/codeworld,google/codeworld,alphalambda/codeworld