Countdown - Call Function When Finished Countdown

dummy.js

/**
 * Countdown - Call Function When Finished Countdown
**/
var Countdown = Class.create({
	initialize: function(pInitialValue, pFunction){
		this.i = pInitialValue;
		this.f = pFunction;
	},
	turn: function(){
		--this.i;
		if(this.i == 0){
			this.f();
		}
	}
});

/* 使い方の例:
var urls = [
  'http://example.cdn/A.lib.js',
  'http://example.cdn/B.lib.js',
  'http://example.cdn/C.lib.js'
];
var hoge = new Countdown(urls.length, function(){
  alert('done!');
});
urls.each(function(url){
  //ここにロードするコードをかく
  hoge.turn();//Ajax.Request完了時に呼ぶとかonloadで呼ぶとか
});
*/