Tip: Press the spacebar to scroll in Safari
Ignore the scrollbar in Safari—there are better ways to scroll through a Web page:
1. Press the spacebar and up/down arrow keys. Press Space to scroll down a page, and shift-Space to scroll up. And the up/down arrow keys scroll the page a line at a time.
2. Roll the center mouse button/wheel on your mouse.
3. Drag two fingers simultaneously on the MacBook or MacBook Pro trackpad. Drag one finger to move the cursor, two to scroll.
These scrolling methods work in many other applications too.
I checked and this also works for Firefox. Oh and you can also reverse scroll meaning move back up the page by pressing shift and the space bar at the same time in either program!