By setting overflow: scroll on an element, I can get scroll function working in a Windows 8 Javascript App.
I noticed that there are 2 types of scrollbars, see the image below.

When hovering the element, the scrollbar on the right side of the image appears. After a few seconds it’ll disappear. At this point, if I choose to scroll using mouse wheel or gesture, the scrollbar on the left side will appear.
Is it possible to control scrolling behavior, so that only the left kind appears?
No. This is determined by the OS depending on whether you are using touch input or mouse/keyboard input.
Per comment: See “the scroll control” in this article.