在javascript中，只要名称与局部变量相同，就可以访问全局变量？

Question

var a="abc";
function(){
var a="efg";
console.log(a);//I need global variable value "abc" here
}
function();

I need the value "abc" in the console. How can I get global variable value?

Answer 1

How can I get global variable value?

use window.a

 var a = "abc"; function a1() { var a = "efg"; console.log(window.a); } a1()

Answer 2

In your specific example, since you used var at global scope, you can access it on the global object, which is accessible via the window global on browsers; so window.a :

 var a="abc"; function example(){ var a="efg"; console.log(window.a);//I need global variable value "abc" here } example();

However , if that global were created by using const , let , or class at global scope, eg:

let a = "abc";

...you would not be able to access it at all within that function, because even though globals created via const , let , or class are globals, they are not properties of the global object.

Answer 3

How can I get global variable value a ?

By not naming your local variable a as well.

var a = "abc";
function example(){
    var b = "efg";
    console.log(a); // The global variable with the value "abc"
    console.log(b); // The local variable with the value "efg"
}
example();

It's local to your function anyway, so you can rename to it anything you want without impacting other functions. Don't use names that you need to access global variables.