Radio button
Encyclopedia
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.
Radio buttons are arranged in groups of two or more and displayed on screen as, for example, a list of circular holes that can contain white space (for unselected) or a dot (for selected). Adjacent to each radio button is normally shown a caption describing the choice that this radio button represents. When the user selects a radio button, any previously selected radio button in the same group becomes deselected. Selecting a radio button is done by clicking the mouse
on the button, or the caption, or by using a keyboard shortcut
.
It is possible that initially none of the radio buttons in a group are selected. This state cannot be restored by interacting with the radio button widget (but it may be possible through other user interface elements).
When used in an HTML
form
, if no button in a group is checked, then no name-value pair is passed when the form is submitted. For example, for a radio button group named Gender with the options Male and Female, the variable Gender would not be passed, even with a blank value.
to select preset stations – when one of the buttons was pressed, other buttons would pop out, leaving the pressed button the only button in the "pushed in" position.
, the HTML element
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
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....
that allows the user to choose only one of a predefined set
Set (computer science)
In computer science, a set is an abstract data structure that can store certain values, without any particular order, and no repeated values. It is a computer implementation of the mathematical concept of a finite set...
of options.
Radio buttons are arranged in groups of two or more and displayed on screen as, for example, a list of circular holes that can contain white space (for unselected) or a dot (for selected). Adjacent to each radio button is normally shown a caption describing the choice that this radio button represents. When the user selects a radio button, any previously selected radio button in the same group becomes deselected. Selecting a radio button 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 button, 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...
.
It is possible that initially none of the radio buttons in a group are selected. This state cannot be restored by interacting with the radio button widget (but it may be possible through other user interface elements).
When used in an HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
form
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...
, if no button in a group is checked, then no name-value pair is passed when the form is submitted. For example, for a radio button group named Gender with the options Male and Female, the variable Gender would not be passed, even with a blank value.
Etymology
Radio buttons were named after the physical buttons used on older car radiosCar audio
Car audio/video , auto radio, mobile audio, 12-volt and other terms are used to describe the sound or video system fitted in an automobile. While 12-volt audio and video systems are also used, marketed, or manufactured for marine, aviation, and buses, this article focuses on cars as the most common...
to select preset stations – when one of the buttons was pressed, other buttons would pop out, leaving the pressed button the only button in the "pushed in" position.
HTML
In web formsForm (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...