Element.Event.js

/*<ltIE9>*/
if (!window.addEventListener) (function(){

var update = function(event){
	event.target.store('$change:last', {
		type: event.type,
		value: event.target.checked
	});
};

Element.Events._change = {
	base: 'change'
};

Element.Events.change = {
	base: 'click',
	condition: function(event){
		var target = event.target, type = target.type, last = target.retrieve('$change:last', {});
		if (type == 'text' || /textarea|select/.test(target.get('tag'))) return event.type == 'change';
		if (type == 'radio' && last.type != 'mousedown' && /up|down|left|right/.test(target.retrieve('$change:key', ''))) return true;	
		return target.checked != last.value;
	},
	onAdd: function(fn){
		this.addEvents(this.retrieve('$change:events', {
			keydown: update,
			mousedown: update,
			_change: function(event){
				if (!/radio|checkbox/.test(event.target.type)) fn.call(this, event);
			},
			keyup: function(event) {
				event.target.store('$change:key', event.key);
				return event.code != 16 && event.key != 'tab';
			}
		}));
	},
	onRemove: function(){
		this.removeEvents(this.retrieve('$change:events')).eliminate('$change:events');
	}
};

})();
/*</ltIE9>*/