JS Object-oriented components

1. Packaging objects

<! DOCTYPE html>
2. Packaging objects
<! DOCTYPE Html>"Content-type"Content="text/html; Charset=utf-8"><title> Untitled Document </title><script>/*var str = ' Hello '; alert (typeof str); Str.charat (0); Str.indexof (' E ') ;*///null undefined//Wrapper object: The base type has its own corresponding wrapper object: String number Boolean/*var str = new String (' Hello ');//alert (typeof str); alert (Str.charat (1)); String.prototype.charAt = function () {};*///var str = ' Hello ';//Str.charat (0); //The base type finds the corresponding wrapper object type, and then wraps the object to give the base type all the properties and methods, and then wraps the object away/*var str = ' Hello '; String.prototype.lastValue = function () {return This.charat (this.length-1);};  Alert (Str.lastvalue ()); o*/varstr ='Hello'; Str.number=Ten; alert (str.number); //undefined</script>
3.
<! DOCTYPE Html>"Content-type"Content="text/html; Charset=utf-8"><title> Untitled Document </title><script>//prototype chain: The connection between the instance object and the prototype, called the prototype chain//The outermost layer of the prototype chain: Object.prototypefunction Aaa () {//this.num =;}//Aaa.prototype.num = ten;Object.prototype.num = -;varA1 =NewAaa (); alert (a1.num);</script>
4.hasownproperty
<! DOCTYPE Html>"Content-type"Content="text/html; Charset=utf-8"><title> Untitled Document </title><script>//hasOwnProperty: See if the property below the object itselfvararr =[];arr.num=Ten; Array.prototype.num2= -;//Alert (arr.hasownproperty (' num ')); //truealert (Arr.hasownproperty ('num2')  );//false</script>
5constructor
<! DOCTYPE Html>"Content-type"Content="text/html; Charset=utf-8"><title> Untitled Document </title><script>//constructor: Viewing the constructor of an object/*function Aaa () {}var A1 = new Aaa (); alert (a1.constructor);  Aaavar arr = [];alert (arr.constructor = = Array); True*//*function aaa () {}//aaa.prototype.constructor = AAA; Each function will have, is automatically generated//aaa.prototype.constructor = Array;var A1 = new Aaa (); alert (A1.hasownproperty = =  Object.prototype.hasOwnProperty); True*//*function Aaa () {}aaa.prototype.name = ' xiaoming '; Aaa.prototype.age = 20; Aaa.prototype = {constructor:aaa, name: ' Xiaoming ', Age:20};var a1 = new Aaa (); alert (a1.constructor);*/function Aaa () {}aaa.prototype.name=Ten; Aaa.prototype.constructor=Aaa; for(varattrinchAaa.prototype) {alert (attr);}</script>
6instanceof
<! DOCTYPE Html>"Content-type"Content="text/html; Charset=utf-8"><title> Untitled Document </title><script>//instanceof: Is there a relationship between the object and the constructor on the prototype chainfunction Aaa () {}varA1 =NewAaa ();//alert (A1 instanceof Object); //truevararr =[];alert (arr instanceof Array);</script>
7.tostring
<! DOCTYPE Html>"Content-type"Content="text/html; Charset=utf-8"><title> Untitled Document </title><script>//toString (): The system objects are all self-bringing, and the objects they write are all based on the prototype chain for object/*var arr = [];alert (arr.tostring = = Object.prototype.toString);//false*//*function Aaa () {}var A1 = new Aaa (); alert (a1.tostring = = Object.prototype.toString); True*///toString (): Turns the object into a string/*var arr = [n/a]; Array.prototype.toString = function () {return this.join (' + ');};  Alert (arr.tostring ()); ' a '*///var num = 255;//Alert (num.tostring (16)); //' FF '//use ToString to make a type of judgment:/*var arr = [];alert (Object.prototype.toString.call (arr) = = ' [Object Array] ');*/ //' [Object Array] 'window.onload=function () {varof = Document.createelement ('iframe');        Document.body.appendChild (of); varIfarray = window.frames[0].        Array; vararr =NewIfarray (); //alert (Arr.constructor = = Array); //false//alert (arr instanceof Array); //falsealert (Object.prototype.toString.call (arr)=='[Object Array]');//true        };</script>
8. Inheritance
<! DOCTYPE Html>"Content-type"Content="text/html; Charset=utf-8"><title> Untitled Document </title><script>//inheritance: Subclasses do not affect the parent class, subclasses can inherit some functions of the parent class (code reuse)//Inheritance of attributes: Calling the constructor of the parent class call//method Inheritance: For in: Copy Inheritance (jquery also uses copy inheritance extend)function Createperson (name,sex) {//Parent Class     This. Name =name;  This. Sex =sex;} CreatePerson.prototype.showName=function () {alert ( This. name);};varP1 =NewCreateperson ('Xiao Ming','male');//p1.showname ();function Createstar (name,sex,job) {//sub-classCreateperson.call ( This, Name,sex);  This. Job =job; }//createstar.prototype = Createperson.prototype;Extend (Createstar.prototype, createperson.prototype); CreateStar.prototype.showJob=function () {};varP2 =NewCreatestar ('Huang Xiaoming','male','actor');p 2.showName (); function extend (obj1,obj2) { for(varattrinchobj2) {Obj1[attr]=Obj2[attr]; }}</script>
9.9 Copying of objects
<! DOCTYPE html>
　　
JS Object-oriented components