Scope in JavaScript

What is Scope?

Scope == variable access. What variables do you have access too when code is run?

By default you are in the root scope which is the window object.

Setting variables within a function will only exist in that function.

Lets say I do the following:

            `function aa () {
                var b = "Hi there!";
            }`

Calling this variable would not be possible without calling this function. As it only exists within this function. Thus, in a way, functions are just more advanced variables. Except they store a larger amount of instructions for a specific purpose within the program.

A root scope simply refers to global variables that are directly attributed to the window.

A child scope refers to the scope within another function. So these scopes are treated seperately.

Using a similar naming system like Andre does with var fun = 5; essentially overwrites a variable just like you would if you did it outside of the function. Meaning the function within JavaScript is essentailly a container for instructions, simplified. Good for referencing a repetitive task that needs to be accessed without rewriting the code over and over again.

Issues that relate to this are called Naming Conflicts and supposedly you will lose access to the root scope by doing this.

Functions can access the global variables, but not the reverse. Meaning that functions can contain their own set of variables and contain them as well as reference variables on the global scope.