toggle

You should be able to toggle this one and get the selected state logged on each click

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normal button

This is a normal button, clicks get logged, no selected attribute, on click the log will always show undefined

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1 2 3

Group of mutually exclusive buttons, only one active at a time. It starts with the 2 selected and after 3 seconds none will. All changes get logged.

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A B C

Mutually exclusive buttons, button C is preselected via existing markup.

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one two three four

This is a plain dropdown whose options have a selected attribute which is handled normally and does not get messed up with that of the toggle buttons or button groups. Initially the three label should show. The state of the selected option will be logged by showing an X in the position of the one selected.