prototypejs Event Delegation syntax for MooTools

// prototypejs element delegation for mootools
// http://api.prototypejs.org/dom/element/on/

(function(addEvent, removeEvent){
    
    var args = arguments;
    
    ['add', 'remove'].each(function(method, l){
        Element.implement(method + 'Event', function(type, selector, fn){
            if(typeof selector == 'function') fn = selector;
            else type = type + ':relay('+selector+')';
            args[l].apply(this, [type, fn]);            
        });
    });


})(Element.prototype.addEvent, Element.prototype.removeEvent);

Usage

$(document.body).addEvent('click', 'a', function(){
    alert('hi');
});