Usually the scroll wheel moves the viewpoint, not the content. I.e. Scrolling the top of the wheel towards yourself (“down”) moves the viewpoint down the page, making the content appear to move up.
Not just usually; this is how WIMP user interfaces have worked since the 80s, regardless if you use a mouse or another device (e.g. keyboard) to scroll the viewport. It’s built into the data model of the UI toolkit.
what else is the scroll wheel for?
Usually the scroll wheel moves the viewpoint, not the content. I.e. Scrolling the top of the wheel towards yourself (“down”) moves the viewpoint down the page, making the content appear to move up.
Not just usually; this is how WIMP user interfaces have worked since the 80s, regardless if you use a mouse or another device (e.g. keyboard) to scroll the viewport. It’s built into the data model of the UI toolkit.
Scrolling the normal direction