This article is about the computer interface element. For the concept in US how to check boxes in pdf law, see Check-the-box. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources.
Unsourced material may be challenged and removed. GUI widget that permits the user to make a binary choice, i.
A caption describing the meaning of the checkbox is normally shown adjacent to the checkbox. Inverting the state of a checkbox is done by clicking the mouse on the box, or the caption, or by using a keyboard shortcut, such as the space bar.
Often, a series of checkboxes are presented, each with a binary choice between two options. Then the user may select several of the choices. Compare this to a radio button, in which only a single option is selectable from several mutually-exclusive choices.
Some applications use checkboxes that allow an indeterminate state in addition to the two provided by a normal checkbox. This third state is shown as a square or dash in the checkbox, and indicates that its state is neither checked nor unchecked. This is most often used when the checkbox is tied to a collection of items in mixed states. The indeterminate state cannot usually be selected by the user, and switches to a checked state when activated.
For example, a checkbox presented to select files to send via FTP might use a tree view so that files can be selected one at a time, or by folder. If only some of the files in a folder are selected, then the checkbox for that folder would be indeterminate. Clicking on this indeterminate checkbox would select all or, less commonly, none of the contained files. Some tri-state checkbox implementations allow the user to toggle among all states, including the indeterminate state, by remembering the mixed state of the items in the collection.
This serves as an undo feature. Setting or clearing a checkbox changes the checkbox’s state with no other side-effects.