Analysis of javascript closure instance analysis _ javascript tips-js tutorial

A closure is an environment expression (usually a function) that has many variables and is bound to these variables. Therefore, these variables are part of the Environment expression. Official explanation
A closure is an environment expression (usually a function) that has many variables and is bound to these variables. Therefore, these variables are part of the Environment expression.
General Explanation
All functions in Javascript are closures. But in general, nested functions produce more powerful closures, which are also what we call "closures" in most cases ". See the following code:

The Code is as follows: