gistfile1.js

(function(){ 
    var events; 
    var check = function(e){ 
        var target = $(e.target); 
        var parents = target.getParents(); 
        events.each(function(item){ 
            var element = item.element; 
            if (element != target && !parents.contains(element)) 
            item.fn.call(element, e); 
        }); 
    }; 
    Element.Events.outerClick = { 
        onAdd: function(fn){ 
            if(!events) { 
                document.addEvent('click', check); 
                events = []; 
            } 
            events.push({element: this, fn: fn}); 
        }, 
        onRemove: function(fn){ 
            events = events.filter(function(item){ 
                return item.element != this || item.fn != fn; 
            }, this); 
            if (!events.length) { 
                document.removeEvent('click', check); 
                events = null; 
            } 
        } 
    }; 
})();