The scroll wheel is one of the few improvements to the basic computer mouse
that has achieved near ubiquity, at least for IBM clones
. It is a small, wide dial mounted vertically between the left and right mouse buttons, a disk with an axis running between the two buttons. Also, in most implementations the wheel can be pressed into the body of the mouse, providing a difficult-to-use "clickability".
The scroll wheel appeared in the mid-90s and quickly gained popularity, appearing on several Logitech
models as well as the Microsoft IntelliMouse
Most often it is used for scrolling the current window
, where it saves having to bring the pointer to the right side of the window, locating the page marker within the scroll bar
, and "left-dragging". It is a pretty significant ergonomic
improvement in that regard. Under Windows
, there is also an odd "scroll-drag" (clicking or holding down the scroll wheel and moving the mouse) which starts a steady variable speed scroll of the current window.
Helpful Hints: you may find it useful to go into the options and set the mouse to scroll one page at a time rather than the default three lines. Also, under Internet Explorer ctrl-scroll will raise and lower non-CSS fonts through the five available size settings.