Widget index / Basic controls · Download this HTML
Ready — try the example.
States and behavior
One selected option, focus, and disabled option. The legend labels the choice as a whole.
Keyboard
Tab enters or leaves the group; arrow keys choose among enabled options; Space selects.
Scope and adaptation
Native inputs with a shared name supply mutual exclusion and keyboard behavior. Separate unrelated groups need different names.
Sources
Microsoft preliminary guide (1995), chapters 7–8 · Modern browser accessibility pattern
Original implementation; system colors are represented by CSS variables. The default 13 px system-font stack is a readable browser adaptation. The 1995 source is preliminary, not a final product specification. Test the target browser and native host before shipping.