JavaScript Prototype继承实践

JavaScript为基于对象及Prototye的语言，个人觉得其Prototype继承要注意的两个方面:
1.子类可以通过prototype链访问父类的方法与属性
2.子类构造函数调用的构造函数，初始化父类属性

function Person(id1, name1){
this.id = id1;
this.name = name1;

};

Person.prototype.getInfo = function(){
alert(this.id + ":" + this.name);
};

function Employee(id, name, salary){
this.salary = salary;
        //调用父类构造函数 
Person.prototype.constructor.call(this,id,name);
};

//构造Prototype链
Employee.extend = function(Person){
function Temp(){};
Temp.prototype = Person.prototype;
Employee.prototype = new Temp();
        //复原Employee构造函数
Employee.prototype.constructor = Employee;
};


Employee.extend(Person);

Employee.prototype.getSalary = function(){
alert(this.salary);
};

Employee.prototype.getInfo = function(){
alert(this.id + ":" + this.name+":"+this.salary);
};

var employee = new Employee("1","ep1",8000);

employee.getInfo();
employee.getSalary();

new Person("2","person2").getInfo();

备注：JavaScript中没有类的概念，上面提到的类实际上都是函数，一般情况下，函数通过new关键字调用后，返回一个对象，它可以看作是此函数的实例，所以我们便称此函数为类，返回的对象为类的实例.