In computing

Computing

Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...

, a checkbox (check box, tickbox, or tick box) is a graphical user interface

Graphical user interface

In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

 element (widget

Widget (computing)

In computer programming, a widget is an element of a graphical user interface that displays an information arrangement changeable by the user, such as a window or a text box. The defining characteristic of a widget is to provide a single interaction point for the direct manipulation of a given...

) that permits the user

User (computing)

A user is an agent, either a human agent or software agent, who uses a computer or network service. A user often has a user account and is identified by a username , screen name , nickname , or handle, which is derived from the identical Citizen's Band radio term.Users are...

 to make multiple selections from a number of options (contrary to a radio button

Radio button

A radio button or option button is a type of graphical user interface element that allows the user to choose only one of a predefined set of options....

 where only one choice is possible) or to have the user answer yes (checked) or no (not checked) on a simple yes/no question.

Normally, checkboxes are shown on the screen as a square box that can contain white space

Whitespace (computer science)

In computer science, whitespace is any single character or series of characters that represents horizontal or vertical space in typography. When rendered, a whitespace character does not correspond to a visual mark, but typically does occupy an area on a page...

 (for false) or a tick mark

Tick (checkmark)

A tick is a mark used to indicate the concept "yes", for example "yes; this has been verified", "yes; that is the correct answer" or "yes; this [item or option] applies to me"...

 or X (for true), as pictured. A caption

Caption

Caption may refer to:*Caption , a small press and independent comic convention held annually in Oxford, England*Closed captioning, used to provide the text of a show's audio portion to those who may have trouble hearing it...

 describing the meaning of the checkbox is normally shown adjacent to the checkbox. Inverting the state

State (computer science)

In computer science and automata theory, a state is a unique configuration of information in a program or machine. It is a concept that occasionally extends into some forms of systems programming such as lexers and parsers....

 of a checkbox is done by clicking the mouse

Mouse (computing)

In computing, a mouse is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons...

 on the box, or the caption, or by using a keyboard shortcut

Keyboard shortcut

In computing, a keyboard shortcut is a finite set of one or more keys that invoke a software or operating system operation when triggered by the user. A meaning of term "keyboard shortcut" can vary depending on software manufacturer...

, such as the space bar

Space bar

thumb|250px|A [[computer keyboard]], Space Bar is on the bottom center of the keyboardThe space bar, spacebar, or space key, is a key on an alphanumeric keyboard in the form of a horizontal bar in the lowermost row, significantly wider than other keys. Its main purpose is to conveniently enter the...

.

Tri-state checkbox

Some applications

Application software

Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...

 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

File Transfer Protocol

File Transfer Protocol is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server...

 might use a tree view

Tree view

A tree view or an outline view is a graphical user interface element that presents a hierarchical view of information. Each item can have a number of subitems...

 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. Continuing to click on the checkbox would alternate between checked (all sub-directories and files selected) and unchecked (no sub-directories or files selected).

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

Undo

Undo is a command in many computer programs. It erases the last change done to the document reverting it to an older state. In some more advanced programs such as graphic processing, undo will negate the last command done to the file being edited....

 feature.

Not actionable

Setting or clearing a checkbox changes the checkbox's state with no other side-effects. Violating this guideline by associating additional actions with the change of state frequently confuses users, because they are used to configuring data in entry controls such as text boxes, radio buttons, and checkboxes and then invoking an action control such as a push button to initiate the action to process the data.

One common exception is to enable or display additional user input elements that are only relevant if the checkbox is either checked or unchecked.

HTML

In web forms

Form (web)

A webform on a web page allows a user to enter data that is sent to a server for processing. Webforms resemble paper or database forms because internet users fill out the forms using checkboxes, radio buttons, or text fields...

, the HTML element

HTML element

An HTML element is an individual component of an HTML document. HTML documents are composed of a tree of HTML elements and other nodes, such as text nodes. Each element can have attributes specified. Elements can also have content, including other elements and text. HTML elements represent...

  is used to display a checkbox.

XAML

In XAML

XAML

Extensible Application Markup Language is a declarative XML-based language created by Microsoft used for initializing structured values and objects. It is available under Microsoft's Open Specification Promise...

 a checkbox is declared as: Label

Unicode

In Unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

, empty and filled checkboxes are represented by code points U+2610 , U+2611 , and U+2612 .

See also

• Elements of graphical user interfaces
  Elements of graphical user interfaces
  Graphical user interfaces, also known as GUIs, offer a consistent visual language to represent information stored in computers. This makes it easier for people with little computer skills to work with and use computer software....
  
  
• Radio button
  Radio button
  A radio button or option button is a type of graphical user interface element that allows the user to choose only one of a predefined set of options....