Operation

A mouse typically controls the motion of a cursor in two dimensions in a graphical user interface (GUI). Clicking or hovering (stopping movement while the cursor is within the bounds of an area) can select files, programs or actions from a list of names, or (in graphical interfaces) through small images called "icons" and other elements. For example, a text file might be represented by a picture of a paper notebook, and clicking while the cursor hovers this icon might cause a text editing program to open the file in a window. (See also point-and-click)
Users can also employ mice gesturally; meaning that a stylized motion of the mouse cursor itself, called a "gesture", can issue a command or map to a specific action. For example, in a drawing program, moving the mouse in a rapid "x" motion over a shape might delete the shape.
Gestural interfaces occur more rarely than plain pointing-and-clicking; and people often find them more difficult to use, because they require finer motor-control from the user. However, a few gestural conventions have become widespread, including the drag-and-drop gesture, in which:
The user presses the mouse button while the mouse cursor hovers over an interface object
The user moves the cursor to a different location while holding the button down
The user releases the mouse button
For example, a user might drag-and-drop a picture representing a file onto a picture of a trash can, thus instructing the system to delete the file.
Other uses of the mouse's input occur commonly in special application-domains. In interactive three-dimensional graphics, the mouse's motion often translates directly into changes in the virtual camera's orientation. For example, in the first-person shooter genre of games (see below), players usually employ the mouse to control the direction in which the virtual player's "head" faces: moving the mouse up will cause the player to look up, revealing the view above the player's head. A related function makes an image of an object rotate, so that all sides can be examined.
When mice have more than one button, software may assign different functions to each button. Often, the primary (leftmost in a right-handedconfiguration) button on the mouse will select items, and the secondary (rightmost in a right-handed) button will bring up a menu of alternative actions applicable to that item. For example, on platforms with more than one button, the Mozilla web browser will follow a link in response to a primary button click, will bring up a contextual menu of alternative actions for that link in response to a secondary-button click, and will often open the link in a new tab or window in response to a click with the tertiary (middle) mouse button.
Different ways of operating the mouse cause specific things to happen in the GUI:
Click: pressing and releasing a button.
(left) Single-click: clicking the main button.
(left) Double-click: clicking the button two times in quick succession counts as a different gesture than two separate single clicks.
(left) Triple-click: clicking the button three times in quick succession.
Right-click: clicking the secondary button.
Middle-click: clicking the ternary button.
Drag: pressing and holding a button, then moving the mouse without releasing. (Use the command "drag with the right mouse button" instead of just "drag" when you instruct a user to drag an object while holding the right mouse button down instead of the more commonly used left mouse button.)
Button chording (a.k.a. Rocker navigation).
Combination of right-click then left-click.
Combination of left-click then right-click or keyboard letter.
Combination of left or right-click and the mouse wheel.
Clicking while holding down a modifier key.
Standard semantic gestures include:
Rollover
Selection
Menu traversal
Drag and drop
Pointing
Goal crossing