How to use global variables correctly by javascript

This article mainly explains "how to correctly use global variables in javascript". The content in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to correctly use global variables in javascript".

Description

1. If you want to access the outermost variable, that is, the global variable, it will cause a greater performance loss than directly accessing the internal variable.

2. Frequently used global variable references can be stored in a local variable.

Example

Const a = 5BX function outter () {const a = 2; function inner () {const b = 2; console.log (b); / / 2 console.log (a); / / 2} inner ();} JavaScript features 1.JavaScript is mainly used to add interactive behavior to HTML pages. 2.JavaScript can be embedded directly into HTML pages, but writing as a separate js file facilitates the separation of structure and behavior. 3.JavaScript has cross-platform features and can run on multiple platforms with the support of most browsers.

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