"Front-end Learning notes" function definition, function call, this

Three ways and characteristics of function definition:
1. function declaration; (feature: Will be pre-set; When you define a function repeatedly, the last definition is valid.) ）
2. function expression;
3. function instantiation; (feature: Only local scopes and global scopes can be accessed!!!) ）

/* Characteristics of the Object instantiation definition function */var person = {Name: "Andy Lau", age:50}; (function () {   var person = {Name: "Andy Lau", age:30};   (function () {     var person = {Name: "Andy Lau", age:10};     Console.log (person.name+person.age+ "old");   }) () })(); -and output 10-year-old Andy Lau, variable step up backwards. var person = {Name: "Andy Lau", age:50};(function () {  var person = {Name: "Andy Lau", age:30};  var func = new Function ("Console.log (person.name+person.age+ ' old ');");  Func ();}) (); -If the new Function () has a 10-year-old Andy Lau, then 10-year-old, or directly 50-year-old.

Function call:

1. function call mode; Add (1)
2. method invocation mode; Mynumber.add (1)
3. constructor call pattern; New Function (...)

/* Function call mode (this) */function Add (i,j) {  console.log (this);//--Window  console.log (arguments);//--> [  (function () {      console.log (this);//--Window  }) ();  var sum = i+j;  return sum;} Add, var mynumber = {  value:1,  add:function (i) {  console.log (this);//--{value:1,add: function () {}}    var helper = function (i) {        console.log (this);//-Window          this.value + = i;//So this cannot be achieved;    }    Helper (i);  }} Mynumber.add (1);

　　

"Front-end Learning notes" function definition, function call, this