Early examples of variables and function declarations in JavaScript

As shown in title, see the following example
(You can use the Chrome browser and then f12/or right-click to review the elements.) Bring up the developer tool and enter the console console input.
(Tip: Shift+enter can break code in the middle of the console input)

var name = "Xiaoming"; (function () {   var name = name | | "Xiao Zhang";  Console.info (name);}) ();//Xiao Zhang (function () {  name = name | | "Xiao Zhang";  Console.info (name);}) (); Xiaoming (function () {  var name2= name;  var name = name | | "Xiao Zhang";  Console.info (name, name2);}) (); Xiao Zhang undefined

The execution is as follows:



The explanations are as follows:
In JavaScript,

function xxx () {  //A heap of code  ... // ...  var name2 = name;  var name = name | | "Xiao Zhang";  A bunch of code}

Execution will become this equivalent form:

function xxx () {  var name2 = undefined;  var name = undefined;  Other Var will also be advanced to the beginning  //heap of code  ... // ...  name2 = name;  Name = Name | | "Xiao Zhang";  A bunch of code}

You can also refer to the Bootstrap Chinese web tutorial advanced in JavaScript for variable and function declarations (hoist)

Date: 2014-11-07

Author: anchor (HTTP://BLOG.CSDN.NET/RENFUFEI)

Early examples of variables and function declarations in JavaScript