javascript-anonymous function, closure application (3).

Mimic block-level scopes

1 functionbox ()2         {3             //A private scope can be implemented by the anonymous function that is contained in my execution4(function()                        5             {6                  for(varI=0 i<5; i++) 7                 {                            8 alert (i);9                 }   Ten                             //The variables used in this One})();//out of Here, destroyed. A              - alert (i); -         } the          -Box ();

This is the global private scope.

1 (function()2        {3             var age =100; 4             alert (age); 5         })(); 6         alert (age);

Private variables

1 //first, private variables are not accessible.2         functionbox ()3         {4             varAge = 100;//private variable, external unreachable5         }6 alert (age);7         8         //but the properties and methods are public.9         functionBox ()Ten         { One              This. age=100;//Properties, Public A              This. run=function()//method, the public -             { -                 return' Running ... ';  the             } -         } -       -         varbox1=NewBox (); + alert (box1.age); -Alert (Box1.run ());

★ Private variable Private function how to access through a public method [is actually the use of the role of the relationship (lexical scope) within the nested method can access variables, methods are common features to implement]

1 functionBox ()2         {3             //Private Variables4             varage=100;5             varnum= ' Jack ';6             7             //Private Functions8             functionRun ()9             {Ten                 returnnum+ ' Running ... ';  One             } A              -              This. Publicgo =function()//externally visible public interfaces, privileged methods -             { the                 returnAge+run (); -             } -              This. getage=function() -             { +                 returnAge ; -             } +         } A          at         varbox=NewBox (); -Alert (Box.publicgo ());//100Jack in operation ...

★ Pass parameters by constructor function

1 functionBox (value)2         {3             varUser=value;4              This. GetUser =function()5             {6                 returnuser;7             }8              This. setuser=function(value1)9             {TenUser=value1; One             } A         } -          -         varbox =NewBox (' Lee '); the alert (Box.getuser ()); -Box.setuser (' OOO ');//can set -Alert (Box.getuser ());

----But the problem is that anonymous functions are created multiple times and not shared resolved as follows

★ Block-level scope access static private variable private function

1(function()2         {3             varuser = ';//Private Variables4box=function(value)//Box does not have var so it is global, constructor5             {6user =value;7             };8Box.prototype.getuser=function()9             {Ten                 returnuser; One             } ABox.prototype.setuser=function(value) -             { -user =value; the             } -              -         })(); -      +         varbox=NewBox (' LEE '); -Alert (Box.getuser ());//LEE +          A         varBox2=NewBox (' KKK '); atAlert (Box.getuser ());//KKK -          -Box2.getuser (' oooo '); -Alert (Box.getuser ());//oooo -          -         //PS: Using prototype causes the method to be shared, and the user becomes a static property. (So-called static properties, which are properties shared in different objects)

★ ★ The module mode-Simple to mention

1 //what is a single case, is always only instantiated once, in fact, is the literal object declaration of the way2 3         varbox = {//The first instantiation, cannot be instantiated the second time, then is a singleton4User= ' Lee ',5Runfunction()6             {7                 return' Travel in ... ';8             }9}

1 //privatization variables and functions2 varbox=function()3         {4             varuser = ' Lee ';//Private Variables5             functionRun ()//Private Functions6             {7                 return' In operation ';8             }9             Ten             return{//This is the method of foreign privilege . OnePUBLICGO:function()  A                 { -                     returnUser +run (); -                 } the             }; -             /* - var obj={//This is the method of foreign privilege - publicgo:function () +                 { - return user +run (); +                 } A             } at return obj; -             */     -         }(); -          -Alert (Box.publicgo ());

javascript-anonymous function, closure application (3).