Question

can anyone spread some light?

Why this .toggle() is breaking the checked/unchecked state of a checkbox?

$('#checkbox').toggle(function(){},function(){});​

when I think, it’s just doing nothing.

crazy demo

_{this was taken from comments of this answer}

Answer 1

toggle() called with two callbacks adds a click event on the targeted element. The event will execute the first callback on even clicks; the second one on odd ones.

Also, and this is why it changes the behaviour, according to the manual:

The implementation also calls .preventDefault() on the event, so links will not be followed and buttons will not be clicked if .toggle() has been called on the element.