JavaScript scopes: The scope of JavaScript

 
 

  
  

  
/***************************************
  
  

  
* The result is to print out the global
  
  

  
****************************************/
  
  

  
var a = ' global ';
  
  

  
(Test () {
  
  

  
Write (a);
  
  

  
})();
  
  

  
/***************************************
  
  

  
* The result is to print out the undefined
  
  

  
****************************************/
  
  

  
var a = ' global ';
  
  

  
(Test () {
  
  

  
Write (a);
  
  

  
var a = ' local ';
  
  

  
})();
  
  

  
/***************************************
  
  

  
* The result is to print out the local global
  
  

  
****************************************/
  
  

  
var a = ' global ';
  
  

  
(Test () {
  
  

  
var a = ' local ';
  
  

  
Write (a + ' \ n ');
  
  

  
})();
  
  

  
Write (a + ' \ n ');
 
 

As can be seen from the above example, the scope of JS is a function body. When a function body defines a local variable with the same name as a global variable, the global variable is overwritten by the local variable.

This article links http://www.cxybl.com/html/wyzz/JavaScript_Ajax/20130318/37230.html