a simple example about javascript module.

moduleVariable.planA=(function(){
	// define some variable privately , it can only be used within this function.
	var someVariable={
		a : 'a',
		b : 'b',
		c : 'c'
	};
	//define a couple of object to include some functions. one for privately , the other one for public.
	var private = {};
	var public = {};
	/*this is private method below , due to the object private can only be visited in this function , so the method belong to 
	this object can only be visited in this function*/
	private.functionA=function(){
		/*Do something*/
		console.log(someVariable.a);// it can visite someVariable;
	}
	private.functionB=function(){
		/*Do something else*/
		console.log(private.functionA);// it can visite private.functionA;
	}
	public.init=function(){
		var a=someVariable.a;
		private.functionA();
		private.functionB();//it can visite variables and functions in this function.	
	}
	return public; //在最后我们返回了public，那么在外部moduleVariable.planA就等于public,moduleVariable.planA可以访问到public的init方法
				   //但是其他所有的变量，私有方法（private），都没有暴露给外部，只在public的init()方法中可以被使用
})();
$(document).ready(function(){
	moduleVariable.planA.init();//Be invoked here.
})