JavaScript's private variables and methods, common variables and methods, and privileged methods, constructors, static common attributes, and static common methods

A private variable: a property and method defined inside a function is called the function's private property and method common variables: Objects and methods created inside a function called this function are common properties and methods
Privileged methods: a common property and method created through this can access both the function and the private properties and methods of the function called the privileged method
Constructor: The object invokes the privileged method at creation time to initialize the properties of the instance, also known as the constructor

  
 

   
  

  
/**
   
  

  
 * 类的内部私有属性、私有方法、特权方法、共有属性和共有方法以及构造器
   
  

  
 * @param id
   
  

  
 * @param bookname
   
  

  
 * @param price
   
  

  
 * @constructor
   
  

  
 */
   
  

  
var BookDemo = function(id,bookname,price){
   
  

  
 /*
   
  

  
 *申明在函数内部的属性和方法是该函数对象的私有属性和私有方法
   
  

  
 */
   
  

  
 var num = 1;// 私有属性
   
  

  
 //私有方法
   
  

  
 function checkId(id){
   
  

  
 return id;
   
  

  
 }
   
  

  

   
  

  
 /**
   
  

  
 * 通过this创建的属性和方法是共有属性和方法 也称为特权方法
   
  

  
 */
   
  

  
 this.bookname = bookname;
   
  

  
 this.getBookName = function(){
   
  

  
 console.info(‘getName特权方法,可以调用类的私有属性和方法:num=‘+num);
   
  

  
 }
   
  

  
 this.setBookName = function(bookname){
   
  

  
 console.info(‘setBookName特权方法‘);
   
  

  
 }
   
  

  
 this.copy = function(){
   
  

  
 console.info(‘copy的共有方法‘)
   
  

  
 }
   
  

  
 /**
   
  

  
 * 在对象创建时候调用这些共有方法初始化实例对象的属性，那么这些共有方法又称为构造器,
   
  

  
 * 在对象被new出来的时候就会被执行 构造器必须有对应的特权方法的实现，否则就会报错
   
  

  
     * This.setbookname is not a function
   
  

  
 */
   
  

  
 this.setBookName(bookname); //如果包含方法则该方法会在初始化的时候就会被创建
   
  

  
 this.getBookName();
   
  

  
}
  
 

To invoke the test method:

 
   
  

  
    
   
var bookDemo = new BookDemo(‘1‘,‘Javascript设计模式‘,‘48.5‘);//由于调用了 this.setBookName 和this.getBookName 属性通过new创建实例的时候就会执行 this.getBookName和 this.setBookName 的特权方法
  
    
   
The result of all outputs is: the Setbookname privileged method and the GetName privileged method, which can invoke the private properties and methods of the class: Num=1
 
   
  

Continue calling test method

 
   
  

  
    
   
console.info(bookDemo.num); //Undefined
 
   
  

Modify Bookdemo to track changes in BookName

  
 

   
  

  
/**
   
  

  
 * 类的内部私有属性、私有方法、特权方法、共有属性和共有方法以及构造器
   
  

  
 * @param id
   
  

  
 * @param bookname
   
  

  
 * @param price
   
  

  
 * @constructor
   
  

  
 */
   
  

  
var BookDemo = function(id,bookname,price){
   
  

  
 /*
   
  

  
 *申明在函数内部的属性和方法是该函数对象的私有属性和私有方法
   
  

  
 */
   
  

  
 var num = 1;// 私有属性
   
  

  
 //私有方法
   
  

  
 function checkId(id){
   
  

  
 return id;
   
  

  
 }
   
  

  

   
  

  
 /**
   
  

  
 * 通过this创建的属性和方法是共有属性和方法
   
  

  
 */
   
  

  
 this.bookname = bookname;
   
  

  
 this.getBookName = function(){
   
  

  
 console.info(‘getName特权方法,可以调用类的私有属性和方法:num=‘+num+",bookname="+bookname);
   
  

  
 }
   
  

  
 this.setBookName = function(bookname){
   
  

  
 console.info(‘setBookName特权方法，bookname=‘+bookname);
   
  

  
 }
   
  

  
 this.copy = function(){
   
  

  
 console.info(‘copy的共有方法‘)
   
  

  
 }
   
  

  
 /**
   
  

  
 * 在对象创建时候调用这些共有方法初始化实例对象的属性，那么这些共有方法又称为构造器,
   
  

  
 * 在对象被new出来的时候就会被执行
   
  

  
 */
   
  

  
 this.setBookName(bookname);
   
  

  
 this.getBookName();
   
  

  
}
  
 

Test

  
 

   
  

  
var bookDemo = new BookDemo(‘1‘,‘Javascript设计模式‘,‘48.5‘);
   
  

  
 bookDemo.setBookName(‘Java设计模式‘);
   
  

  
 /**
   
  

  
 * 输出依次为：setBookName特权方法，bookname=Javascript设计模式
   
  

  
 * getName特权方法,可以调用类的私有属性和方法:num=1,bookname=Javascript设计模式
   
  

  
 * setBookName特权方法，bookname=Java设计模式
   
  

  
 */
  
 

Static common method and static common property of class

  
 

   
  

  
/***
   
  

  
 * 通过new创建对象是，由于类外面通过点语法创建的属性和方法没有执行到，所以新创建的对象无法获取到他们
   
  

  
 * 但是可以通过类来获取，所以称之为类静态共有属性和方法
   
  

  
 * @type {boolean}
   
  

  
 */
   
  

  
BookDemo.isChinese = true; //类静态共有属性
   
  

  
//类静态共有方法
   
  

  
BookDemo.checkBookName = function(){
   
  

  
 console.info(‘通过点方法创建的类静态共有方法,只能改类自己直接方法，不能通过new创建对象来访问‘);
   
  

  
}
   
  

  
/**
   
  

  
 * 通过prototype创建的属性和方法可以通过this来访问，所以通过prototype创建的属性和方法称之为共有属性和方法
   
  

  
 * @type {{isJsBook: boolean, display: BookDemo.display}}
   
  

  
 */
   
  

  
BookDemo.prototype = {
   
  

  
 isJsBook : true,
   
  

  
 display : function(){
   
  

  
 console.info(‘外部通过prototype创建的方法可以访问该函数内部的属性，bookname=‘+this.bookname);
   
  

  
 }
   
  

  
}
  
 

Test

 
   
  
 
    
   
< Span class= "PLN" >console  info   ( bookdemo   ischinese     //undefined   
 
    
   
   bookdemo   checkbookname   ();    //the class static common method created by the point method, can only be changed to the class itself direct method, cannot create object through new to access   
 
    
   
 Bookdemo   display   ();  //the properties inside the function can be accessed through a method created by prototype, bookname=undefined   
 
   
  

From for notes (Wiz)

JavaScript's private variables and methods, common variables and methods, and privileged methods, constructors, static common attributes, and static common methods