MooTools-1.2.3 document.id

Document.implement({
	
	id: (function(){
		
		var types = {

			string: function(id, nocash, doc){
				id = doc.getElementById(id);
				return (id) ? types.element(id, nocash) : null;
			},
			
			element: function(el, nocash){
				$uid(el);
				if (!nocash && !el.$family && !(/^object|embed$/i).test(el.tagName)){
					var proto = Element.Prototype;
					for (var p in proto) el[p] = proto[p];
				};
				return el;
			},
			
			object: function(obj, nocash, doc){
				if (obj.toElement) return types.element(obj.toElement(doc), nocash);
				return null;
			}
			
		};

		types.textnode = types.whitespace = types.window = types.document = $arguments(0);
		
		return function(el, nocash, doc){
			if (el && el.$family && el.uid) return el;
			var type = $type(el);
			return (types[type]) ? types[type](el, nocash, doc || document) : null;
		};

	})()

});