A radio button or option button is a graphical control element that allows the user to choose only one of a predefined set of mutually exclusive options. The singular property of a radio button makes it distinct from

checkbox A checkbox (check box, tickbox, tick box) is a graphical widget that permits the user to make a binary choice, i.e. a choice between one of two possible mutually exclusive options. For example, the user may have to answer 'yes' (checked) or 'n ...

es, where the user can select and unselect any number of items. 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). Each radio button is normally accompanied by a label describing the choice that the radio button represents. The choices are mutually exclusive; when the user selects a radio button, any previously selected radio button in the same group becomes deselected (making it so only one can be selected). Selecting a radio button is done by clicking the mouse on (or touching the screen over) 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 unselected state cannot be restored by interacting with the radio button widget, though 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 ''Sex'' with the options ''Male'' and ''Female'', the variable ''Sex'' would not be passed, even with a blank value.

Etymology

Radio buttons were named after the physical buttons used on older

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmi ...

s 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 forms, the HTML element is used to display a radio button. Example: A group of attributes is defined by name. In one group, only one radio button can be chosen.

Unicode

Version 6 of the

Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, wh ...

standard includes a character designated to represent a radio button, (🔘) at code point 128,280 (U+1F518), found in th
Miscellaneous Symbols and Pictographs
section. Similar characters are the

mathematical operator In mathematics, an operator is generally a mapping or function that acts on elements of a space to produce elements of another space (possibly and sometimes required to be the same space). There is no general definition of an ''operator'', bu ...

as well as and . The font

Wingdings Wingdings is a series of dingbat fonts that render letters as a variety of symbols. They were originally developed in 1990 by Microsoft by combining glyphs from Lucida Icons, Arrows, and Stars licensed from Charles Bigelow and Kris Holmes. Ce ...

2 contains at position 153 and 158 glyphs that look like radio buttons.

References

External links

RFC1866
the HTML 2.0 specification, which defined radio buttons on the web.

*Usage of radio buttons i

* {{Graphical control elements Graphical control elements

Etymology

HTML

Unicode

See also

References

External links