var Person = function(name,sex){
    this.name = name;
    this.sex = sex;     
    var _privateVariable = "";//私有變量    
    //構造器中定義的方法，即為私有方法
    function privateMethod(){   
        _privateVariable = "private value";
        alert("私有方法被調用！私有成員值：" + _privateVariable);             
    }
    privateMethod(); //構造器內部可以調用私有方法            
}

Person.prototype.sayHello = function(){
    alert("姓名：" + this.name + "，性別：" + this.sex);
}

var p = new Person("菩提樹下的楊過","男");      
p.sayHello();

//p.privateMethod();//這里將報錯，私成方法無法被實例調用
alert(p._privateVariable);//顯示: undefined

var Person = function(){    
    var salary = 0.0;

    this.setSalary = function(value){
        salary = value;
    }

    this.getSalary = function(){
        return salary;
    }
}

var p = new Person();

p.setSalary(1000);
alert(p.getSalary());//返回1000
alert(p.salary);//返回undefined