- blogfunction Parent(username){
- this.username = username;
- this.hello = function(){
- console.log('hello ' + this.username);
- }
- }
- Parent.prototype.sayMorning = function(){
- console.log('good morning ' + this.username);
- }
- function Child(username,password){
- //通过以下3行实现将Parent的属性和方法追加到Child中,从而实现继承
- //第一步:this.method是作为一个临时的属性,并且指向Parent所指向的对象,
- //第二步:执行this.method方法,即执行Parent所指向的对象函数
- //第三步:销毁this.method属性,即此时Child就已经拥有了Parent的所有属性和方法
- this.method = Parent;
- this.method(username);//最关键的一行
- delete this.method;
- this.password = password;
- this.world = function(){
- console.log(this.password);
- }
- }
- var parent = new Parent("zhangsan");
- var child = new Child("lisi","123456");
- parent.hello();
- parent.sayMorning();
- child.hello();
- child.world();
- function Parent(username){
- this.username = username;
- this.hello = function(){
- console.log(this.username);
- }
- }
- Parent.prototype.sayMorning = function(){
- console.log('good morning ' + this.username);
- }
- function Child(username,password){
- Parent.call(this,username);
- this.password = password;
- this.world = function(){
- console.log(this.password);
- }
- }
- var parent = new Parent("zhangsan");
- var child = new Child("lisi","123456");
- parent.hello();
- parent.sayMorning();
- child.hello();
- child.world();
- // child.sayMorning(); 通过prototype 添加的方法和属性,不能用来继承
- function Parent(username){
- this.username = username;
- this.hello = function(){
- console.log(this.username);
- }
- }
- Parent.prototype.sayMorning = function(){
- console.log('good morning ' + this.username);
- }
- function Child(username,password){
- Parent.apply(this,new Array(username));
- this.password = password;
- this.world = function(){
- console.log(this.password);
- }
- }
- var parent = new Parent("zhangsan");
- var child = new Child("lisi","123456");
- parent.hello();
- parent.sayMorning();
- child.hello();
- child.world();
- // child.sayMorning(); 通过prototype 添加的方法和属性,不能用来继承
4、继承的第四种方式:原型链方式,即子类通过 prototype 将所有在父类中通过 prototype 追加的属性和方法都追加到 Child,从而实现了继承
- function Person(){
- }
- Person.prototype.hello = "hello";
- Person.prototype.sayHello = function(){
- console.log(this.hello);
- }
- function Child(){
- }
- Child.prototype = new Person();//这行的作用是:将Parent中将所有通过prototype追加的属性和方法都追加到Child,从而实现了继承
- Child.prototype.world = "world";
- Child.prototype.sayWorld = function(){
- console.log(this.world);
- }
- var c = new Child();
- c.sayHello();
- c.sayWorld();
- 通过prototype 添加的方法和属性,不能用来继承
- function Parent(hello){
- this.hello = hello;
- }
- Parent.prototype.sayHello = function(){
- console.log(this.hello);
- }
- function Child(hello,world){
- Parent.call(this,hello);//将父类的属性继承过来
- this.world = world;//新增一些属性
- }
- Child.prototype = new Parent();//将父类的方法继承过来
- Child.prototype.sayWorld = function(){//新增一些方法
- console.log(this.world);
- }
- var c = new Child("zhangsan","lisi");
- c.sayHello();
- c.sayWorld();
- 可以继承通过prototype 添加的方法和属性
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