关于原型、原型链和原型继承的理解

1 // demo1 --- 原型    
2         var Person = function () { }
3         Person.prototype = {
4             name: "zhangsan"
5         }
6         var p = new Person();
7         console.log(p);

 1         // demo2 --- 原型链
 2         var Person = function () { }
 3         Person.prototype.gongzi = 5000;
 4         Person.prototype.say = function () {
 5             console.log("天气很好")
 6         }
 7         var Programmer = function () {}
 8         Programmer.prototype = new Person()
 9         Programmer.prototype.gongzi = 15000;
10         Programmer.prototype.wcd = function () {
11             console.log("天气也很好")
12         }
13         var p = new Programmer()
14         console.log(p)

 1         // demo3 --- 原型链继承
 2         function Person(name, age) {
 3             this.name = name;
 4             this.age = age;
 5         }
 6         Person.prototype.sayHello = function () {
 7             console.log("名字叫 " + this.name)
 8         }
 9         function Student() {}
10         Student.prototype = new Person(‘zhangsan‘,18);//此步骤为继承 父 中的属性
11         Student.prototype.grade = 3;
12         Student.prototype.test = function(){
13             console.log(this.grade);
14         }
15         var s = new Student();
16         console.log(s);