If you use Tab Mix Plus add-on for Firefox and enabled the option to allow scrolling to select tabs, you’ll love this similar Alt-Tab replacement using AutoHotKey script.

Let’s say you have 5 windows showing up in your taskbar and the second one is currently active, place your mouse pointer anywhere on the taskbar and scroll up and down to switch to next (third) and previous (first) windows respectively while this script is running. While scrolling down as you reach the last window, the very first window in the taskbar comes to front as expected. Similarly when the first window is activated while scrolling up, you jump to very last window when you continue.

The following screencast (800×600, 15 sec, 600 KB) demonstrates this (opens in a new tab/window):

Download AHK file (need to have AutoHotKey installed) or the zipped exe version

You might realize that using Alt-Tab is easier to switch to windows that are not adjacent to each other, but for switching between two windows next to each other, this is pretty useful.

Credits: Lacrossa and lanux128