> But when scroll wheels were introduced, the scroll bar became less necessary.
This isn't true; scroll wheels are more convenient than using the scroll bar for progressing through a document sequentially, but there's no facility for absolute positioning using a scroll wheel. You can't move to a specific point on the page with the wheel, and can only move in one direction or the other at a speed limited by how fast you can physically spin the wheel on the mouse.
Probably the best alternative to a scrollbar for absolute positioning that I've ever seen is the "document map" feature of some text editors, which provides a vertical thumbnail of the entire document in a column that works similarly to the way a mini-map in a game works: you see the layout of the document, zoomed out, and can click on exactly where you want to go.
This isn't true; scroll wheels are more convenient than using the scroll bar for progressing through a document sequentially, but there's no facility for absolute positioning using a scroll wheel. You can't move to a specific point on the page with the wheel, and can only move in one direction or the other at a speed limited by how fast you can physically spin the wheel on the mouse.
Probably the best alternative to a scrollbar for absolute positioning that I've ever seen is the "document map" feature of some text editors, which provides a vertical thumbnail of the entire document in a column that works similarly to the way a mini-map in a game works: you see the layout of the document, zoomed out, and can click on exactly where you want to go.