<code lang="JavaScript">
Object.extend(Prototype,
	{
		scriptPath:
			$$('script').find( 
					function (s) {
						return (s.src && /prototype.*js$/i.test(s.src))
					}
				).src.replace(/prototype.*js$/i,''),
		includeJS: function (file) {
			var elScript = Element.create('script',{
				type:'text/javascript',
				src:file
			});
			var myPromise = (function () {$$('head')[0].appendChild(this);}).bind(elScript);
			Prototype.Promise(
				'$$("head").length>=1',
				(function () {
					$$('head')[0].appendChild(this);
				}).bind(elScript)
			);
		},
		includeCSS: function (file) {
			var elLink = Element.create('link',{
				type:'text/css',
				rel:'stylesheet',
				href:file
			});
			Prototype.Promise(
				'$$("head").length>=1',
				(function () {
					$$('head')[0].appendChild(this);
				}).bind(elLink)
			);
		},
		Promise: function (condition,action,interval) {
			if (typeof interval=='undefined') interval=1;
			//Promise to do this now, or whenever (condition) is met
			if (eval(condition))
				action();
			else 
				new PeriodicalExecuter(
					function (pe) {
						Prototype.Promise.bind(pe,condition,action,interval)();
					},
					2
				);
			if (this.stop) this.stop();
		}
	}
);
</code>