Links are your basic call back mechanism. You can attach links to any element you want. See Link-o-matic for more link examples.
	Here is a normal link, attached to an anchor:
	this link is clicked n times
	
	Same as above, but this time a link that records a state change.
	this link is clicked n times
	
	And here is a link attached to a button element, with a nested label:
	
	
	But you could also attach a link to an input/button element, and attach an AttributeModifier
	to it to display the number of clicks: