JS Object-oriented (ii)---inheritance

First, object-oriented inheritance

1, Analysis: On the basis of the original object, slightly modified to get a new object, and does not affect the original object function

2. How to add inheritance---copy inheritance

Properties: Call

Method: For in

/* Inheritance: Subclasses do not affect the parent class, subclasses can inherit some of the functionality of the parent class (code reuse) property inheritance: Call the parent class to construct the 1 function of the calling method's inheritance: For in   copy inherits *///parent class function Createperson (Name,sex) { this.name = Name;this.sex = sex;} CreatePerson.prototype.showName = function () {alert (this.name)}var p1 = new Createperson (' Xiao Ming ', ' Man ') p1.showname ()   / /xiaoming//Subclass function Createstar (name,sex,job) {createperson.call (this,name,sex); this.job = job;} Copy inheritance Extend (Createstar.prototype,createperson.prototype) var p2 = new Createstar ("Jay", ' Male ', ' singer ');p 2.showName ();    Jay//object-oriented copy copy to prevent content that affects the parent class object function extend (OBJ1,OBJ2) {for (Var attr in obj2) {obj1[attr] = obj2[attr];}}

Then follow the way to do a window dragging the demo, you can ruthlessly click here, to view

Ii. Other forms of inheritance (not many)

1. Class-based inheritance: Using constructors (classes) to inherit the way

/*js is not a class concept, but we can think of the constructor as a class, which is transformed from the backend * *///parent function Aaa () {this.name = ' xiaoming ';} Aaa.prototype.showName = function () {alert (this.name)}//subclass function Bbb () {}//This sentence is class-inherited Bbb.prototype = new Aaa ();//fix point problem Bbb.prototype.constructor = Bbb;var B1 = new Bbb (); B1.showname ()    ; Xiao ming

But in fact the above is still a bit problematic, if the name is an array, the parent class property will be modified, so the example is complete as follows

/* 1, JS is not the concept of class, but we can think of the constructor as a class, this way is transformed from the back end of the 2, to do property and method inheritance, to separate inherit  * *///parent function Aaa () {this.name = [];} Aaa.prototype.showName = function () {alert (this.name)}//sub-class function Bbb () {Aaa.call (this)}//this is a constructor, there is no property or method in this function , avoid attribute inheritance var F  = function () {}f.prototype = aaa.prototype;//so when B receives the prototype, it can only receive the method, cannot receive the property Bbb.prototype = new F (); Bbb.prototype.constructor = Bbb;var B1 = new BBB () B1.name.push (4); var b2 = new BBB (); alert (b2.name)    ; The

2. Prototype inheritance: Using prototypes to implement object inheritance objects

var a = {name: ' xiaoming '}var b = cloneobj (a); b.name = "Little Red" alert (a.name);    Xiao Ming Alert (b.name);  Red function cloneobj (obj) {//This method is called prototype inheritance var F = function () {}; F.prototype = Obj;return new F ();}

Summarize:

Copy inheritance: Universal , available with new or no new

Class-Type Inheritance: New constructor

Prototype inheritance: Objects without new

JS Object-oriented (ii)---inheritance