javascript常用继承方式.

 

//原型链继承

function Parent() {
this.name = 'per';
}
function Child() {
this.age = 20;
}
Child.prototype = new Parent();
var child = new Child();
console.log(child.name + " " + child.age)//per 20

//构造函数继承

 function Parent(age) {
this.name = 'person';
this.age = age;
}
function Child(age) {
Parent.call(this, age)
}
var child = new Child(20)
console.log(child.name + " " + child.age)//per 20

// 组合继承

 function Parent(age) {
this.name = 'per';
this.age = age;
}
Parent.prototype.sayAge = function () {
return this.name + ' age is ' + this.age;
}
function Child(age) {
Parent.call(this, age)
}
Child.prototype = new Parent();
var child = new Child(21);
console.log(child.sayAge())//per age is 21