What you need to know about mice, trackballs and trackpads Navigating the screen in a graphical environment is made possible by a mouse, trackball or trackpad. The mouse , the computer's basic pointing device, comes in many shapes and sizes with a wide range of alternatives.
Older mice have a single button that lets users click or select items on the screen.
Moving the mouse from side to side rolls a small ball on the underside of the device, and that movement tells the computer where to move the cursor on the screen. You can give the computer a command by pointing the cursor to a menu on the screen and clicking a button on the mouse. Newer mice have two, and sometimes three buttons, offering more advanced features such as alternative menus and navigation enhancements. Other high-end features include mechanical or optical tracking, infrared or radio remote capabilities, and ergonomic styling. A trackball .