The radio widget displays an HTML `<input type="radio">` that reflects whether a given tiddler field has a specified value. Selecting the radio button sets to the tiddler field to the value.
The content of the `<$radio>` widget is displayed within an HTML `<label>` element also containing the radio button. This means that clicking on the content will have the same effect as clicking on the button itself.
|field |The field of the //tiddler// bound to the radio button|
|index|<<.from-version "5.1.14">> The index of the //tiddler// being [[DataTiddler|DataTiddlers]] bound to the radio button<<.tip "takes precedence over //field//">>|
|value |The value for the //field// or //index// of the //tiddler//|
Using the radio widget in index mode requires the //index// attribute to specify the name of the index of a [[DataTiddler|DataTiddlers]] to which the specified //value// is assigned.