using LABjs to load from a CDN, with simple error detection (& timeout), and a local load fallback

gistfile1.js

function loadOrFallback(scripts,idx) { 
	var successfully_loaded = false;  
	function testAndFallback() {   
		clearTimeout(fallback_timeout);
		if (successfully_loaded) return; // already loaded successfully, so just bail
		try {
			scripts.tester();
			successfully_loaded = true; // won't execute if the previous "test" fails   
			scripts.success();
			// console.log("success: " + scripts.src[idx]);
		} catch(err) {
			if ( idx < scripts.src.length-1 ) {
				loadOrFallback(scripts,idx+1);
			}
			else if( scripts.loopRetry-- ){
				loadOrFallback(scripts,0);
			}
		}   
	}   
  
	if (idx == null) idx = 0;  
	$LAB.script(scripts.src[idx]).wait(testAndFallback);
	var fallback_timeout = setTimeout(testAndFallback, scripts.timeout); 
}
loadOrFallback({
	src: [	"http://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js",
		"http://lib.sinaapp.com/js/jquery/1.5.1/jquery.min.js",
		"./js/jquery.min.js" ],
	tester: function() { jQuery(""); },
	success: function() {
		$LAB
		.script('./js/plugins/jquery.select.js')
		.script('./js/plugins/jquery.nav.js')
		.script('./js/plugins/jquery.tips.js').wait();
	},
	timeout: 1000 // only wait 1 second
	loopRetry: 2
});