Scope determines the accessibility of variables from different parts of your code.

JavaScript has two types of scopes: Global scope and Local scope.

Global scope:

When a variable is ''globally scoped'', that variable is available from anywhere in your program. If the variable is declared outside a function or a block outside a function, leads to it being a globally scoped.

Local scope :

When variables are declared within a function or a block, they are locally scoped. It means that they can only be accessed inside the function or the block they were declared in.

Local scope variables are divided into:

• Function scoped variables: a function scoped variable means that the variable defined within a function will not be accessible from outside the function.

• Block scoped variables: a block scoped variable means that the variable defined within a block will not be accessible from outside the block. A block can reside inside a function, and a block scoped variable will not be available outside the block even if the block is inside a function.

There are three different keywords used to declare a variable in JavaScript. These are: var, let and const.

Var is function scoped, let and const are block scoped.

Here are some examples about var and let: