NanoLoader.js

// Nano Loader
(function() {
	nano = {
		v: "1.0",
		load: function(u, cb) {
			var s = document.createElement('script');
			s.type = 'text/javascript';
			s.src = u;
			s.onload = cb;
			s.onreadystatechange = function() {
				if (this.readyState == 'complete' || this.readyState == 'loaded') { cb(); }
			};
			document.getElementsByTagName('head')[0].appendChild(s);
		},
		mt: function(cb) {
			if (typeof(MooTools)=="undefined") {nano.load('http://ajax.googleapis.com/ajax/libs/mootools/1.2.4/mootools-yui-compressed.js', cb);}
		},
		jq: function(cb) {
			if (typeof(jQuery)=="undefined") {nano.load('http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js', cb);}
		}
	};
})();

// Bookmarklet
javascript:(function(){nano={v:"1.0",load:function(u,cb){var s=document.createElement('script');s.type='text/javascript';s.src=u;s.onload=cb;s.onreadystatechange=function(){if(this.readyState=='complete'||this.readyState=='loaded'){cb();}};document.getElementsByTagName('head')[0].appendChild(s);},mt:function(cb){if(typeof(MooTools)=="undefined"){nano.load('http://ajax.googleapis.com/ajax/libs/mootools/1.2.4/mootools-yui-compressed.js',cb);}},jq:function(cb){if(typeof(jQuery)=="undefined"){nano.load('http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js',cb);}}};})();