How JavaScript private members are implemented

I bought a book before, "JavaScript advanced Programming," Nicholas C.zakas.

Generally speaking, this book is still possible, but after reading this book still left a few problems have been bothering me, such as JS private variable implementation, prototype, and so on, after their own series of tests, and now finally figured out.

A lot of books are saying that JavaScript is not really implementing JavaScript private members, so at the time of development, the Unified Convention __ Two underscore start as a private variable.

Later, the feature of the closure in JavaScript was discovered, which completely solved the problem of JavaScript private members.

function　testFn(){
　var　_Name;//定义Javascript私有成员
　this.setName　=　function(name){
　　_Name　=　name;　//从当前执行环境中获取_Name
　}
　this.getName　=　function(){
　　return　_Name;
　}
}//　End　testFn
var　test　=　testFn();
alert(typeof　test._Name　===　"undefined")//true
test.setName("KenChen");

Test._name cannot be accessed at all, but can be accessed using object methods because closures can fetch information from the current execution environment.

Next, let's see how the shared members are implemented.

function　testFn(name){
　this.Name　=　name;
　this.getName　=　function(){
　　return　this.Name;
　}
}
var　test　=　new　testFn("KenChen");
test.getName();　//KenChen
test.Name　=　"CC";
est.getName();//CC　

Next, let's look at how the class static variable is implemented.

function　testFn(){
}
testFn.Name　=　"KenChen";
alert(testFn.Name);//KenChen
testFn.Name　=　"CC";
alert(testFn.Name);//CC

About Portotype, succession and so on after posting narration.