Mouse autoscroll
Autoscroll is a feature activated by the middle mouse button (usually the scroll wheel) that enables fast navigation of view width. For historic reasons, most Linux applications treat a middle-click as a paste command. It might be desirable to imitate the Windows behavior, by initiating automatic scrolling when clicked on a blank area of a web page.
Firefox
See the Firefox#Middle-click behavior section.
Chromium-based
See the Chromium#Enabling autoscroll with middle mouse button section.