How to implement protected properties in javascript [ES5]

protected.js

/**
 * How to implement protected properties in javascript [ES5]
 * 
 * @author      Steve Hoang <particles4dev>
 * @version     
 * @since       0.1 
 * @inspiration	WebReflection <link>
 *
**/

(function(){
var ProtectedPropertype, Check, Extends, AccessDeniedError;
	AccessDeniedError = function(){
		var name = "Access Denied Error";
    	var message = ": protected !!!";
    	this.getMessage = function(){
    		return name + " " + message;
    	}
    }
    /**
     *	ProtectedPropertype Class
     *
     *	Description
   	**/
	ProtectedPropertype = function(v){
		/** 
		 * Private property
		**/
    	var that = this;
		var value = v;
    	/** 
    	 * Public property
    	**/
    	this.obj = null;
    	this.setObject = function(o){
        	this.obj = o;    
    	};
    	this.enumerable = true;
    	this.configurable = true;
    	// Define the getter
    	this.get = function get(){
        	var c = Check(that.obj, get.caller);
        	if(c == Extends.ISPROTECTED) return new ProtectedPropertype(value);
        	return value;
   		};
    	// Define the setter
    	this.set = function set($value) {
        	Check(that.obj, set.caller);
        	value = $value;
    	};  
	};

	this.Check = function(object, caller){
		/** 
		 * Private property
		**/
    	if (caller === Check) {
        	return;
    	}
    	if (caller === Extends) {
        	return Extends.ISPROTECTED;
    	}
    	if (caller) {
        	for (var key in object) {
           		if (object[key] === caller){
                	return;
            	}
        	}
   		}    
    	throw new AccessDeniedError();
	};

  	Extends = function(result){
   		var source, obj = {}, prop, ft, fs = function(){}, s;
    
    	for(var i = 1, len = arguments.length; i < len; i++){
      		source = arguments[i];
      		if (source && typeof source == "object") {        
       			for (prop in source) {
          			obj[prop] = source[prop];
        		}
      		}
      		else if (source && typeof source == "function") {
        		//stupid ; will fix it
        		ft = new fs();
        		s  = new source();
        		for (prop in s) {
          			ft[prop] = s[prop];
        		}
        		source.prototype = ft;
        		fs = source;
      		}
    	}
    	var tg = new fs();
    	for(prop in obj){
      		tg[prop] = obj[prop];
   		}
    	result.prototype = tg;
    	return result;
  	};
  	Extends.ISPROTECTED = 0;

  	Object.defineProtectedProperty = (function(defineProperty){
    /**
     *  Class
     *
     *  ads
    **/
      	return function defineProtectedProperty(object, key, description){       
          	description.setObject(object);
          	defineProperty(object, key, description);
      	};
  	}(Object.defineProperty));


console.group("Step 1 : Create object");
var monkey = {
    action: function () {
        this._eatBanana();
    }
};
console.log("var monkey = ");
console.log(monkey);
console.groupEnd();

console.group("Step 2 : Add 'protected' method _eatBanana");
Object.defineProtectedProperty(
    monkey, "_eatBanana",
    new ProtectedPropertype(function () {
        console.log(this._eating);
    })
);
console.log("var monkey = ");
console.log(monkey);
console.groupEnd();

console.group("Step 3 : Add 'protected' property _eating");
Object.defineProtectedProperty(
    monkey, "_eating",
    new ProtectedPropertype("yum yum yum")
);
console.log("var monkey = ");
console.log(monkey);
console.groupEnd();

console.group("Step 4 : Method call monkey._eatBanana();");
try {    
    monkey._eatBanana();
} catch(e) {
    console.log(e.getMessage());
}
console.groupEnd();

console.group("Step 5 : Property access monkey._eating");
try {
    monkey._eating = "change text";
} catch(e) {
    console.log(e.getMessage());
}
console.groupEnd();

console.group("Step 6 : monkey.action();");
monkey.action();
console.groupEnd();

console.group("Step 7 : Extends");
var human = function(){
  	this.saySomething = function(){
     	console.log("i am human not a monkey"); 
  	}
};
var man = Extends(function(){
  	var that = this;
  	for (prop in that) {
    	if(that[prop] instanceof ProtectedPropertype)
      		Object.defineProtectedProperty(that, prop, that[prop]);
  	}
}, monkey, human);
console.log("var man = ");
console.log(man);
console.groupEnd();

console.group("Step 8 : New man");
var john = new man();
console.log("var john = ");
console.log(john);
console.groupEnd();

try {    
    john._eatBanana();
} catch(e) {
    console.log(e.getMessage());
}
john.saySomething();
console.log(john instanceof human);
console.log(john instanceof man);
//console.log(john instanceof monkey);
})();