If you want to know the lexical scope of JavaScript, you need to know about the scope first.
Two types of Scope (Layer Special) are used to run JavaScript code or programs such as Global Scope and Functional/Local Scope. When executing JavaScript engine code or programs, look for variables from Local Scope to Local Scope or from Local Scope to Global Scope.
That is, the layer or layer to execute the code or program of the JavaScript engine is called the scope.
