[Basic]javascript----This

Excerpt from the advanced programming of JavaScript

Ps: Very good book, you can go directly to read, here is just record. Recommend a computer ebook website: the Leather Bookstore

Search information: Mdn,w3cschool,google

• the execution environment of an anonymous function is global , so this is pointing to the window
• function is called, and its active objects are automatically given two special variables: This and arguments
• Call (), apply (), bind () point to its specified object

This: How the function is called determines the value of this

----in global context

Point to window, point to undefined in "use strict" mode

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In a word, this is determined by the run-time context , who is the runtime context, and this points to who

function A () {    returnthis  }

A function is in the global environment

A ()       //equivalent to the following WINDOW.A ()

So this is pointing to window

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var name= "the Window"; var object ={    "My object",    function() {        return function () {            returnthis. Name;  anonymous function, Closure          };}    ; Alert (Object.getnamefunc () ()); The Window

Object.getnamefunc () returns an anonymous function because the execution environment of an anonymous function is global , so this point points to the window

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var name= "the Window"; var object ={    "My object",    function() {
var that =this        returnfunction() {            return to that . Name;  anonymous function, Closure        };     // The Object

var = This is the object in the environment, so this is a pointer to object, which is obvious, so that.name is also pointing to Object.name

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var o = {prop:37}; function Independent () {  returnthis = Independent;     // Logs 37

Equivalent to

var o = {prop:37};
O.F = function () {
Return This.prop
}
Console.log (O.F ()); Logs 37

So obviously this is in O environment, so this is pointing to O

--------------------------

var name= "the Window"; Var object ={"name": "My Object"};console.log (    (object.getname=function() {    the anonymous function assigns a value and executes, so point to window        returnthis. Name;    }) ());    //  Console.log (Object.getname ());  // My Object

There is a C-pointer feeling, the brain is a direction of the arrow, want the other end of the arrow, you know this point to WHO

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1 var name = "the Window"; 2 3 var object = {4     Name: "My Object", 5     getname:function() {6         return This}9 (object.getname = Object.getname) (); The Window    

1. The 9th line will appear in Chrome

Uncaught Typeerror:cannot Read Property ' GetName ' of undefined

and IE11 under no problem, why????

[Basic]javascript----This