The Complete JavaScript Guide - Scope

In JavaScript, there are two types of variable scopes:

• Global Scope : Variables declared Globally (outside of any function) have Global Scope and Global variables can be accessed from anywhere in a program

	let globalLet = "This is a global variable";

	function fun() {
	let localLet = "This is a local variable";

	console.log(globalLet); 
	console.log(localLet); 
	}
	fun();


output ---> //This is a global variable
            // This is local varibale
        

• Local Scope : Variables declared inside a function become local to the function. Local variables are created when a function starts and deleted when the function is executed.

	let globalLet = "This is a global variable";

	function fun() {
	let localLet = "This is a local variable";

	
	}
	fun();
           
        console.log(globalLet); // This is a global variable
	console.log(localLet); 

output ---> // This is global variable

We are still able to see the value of the global variable, but for local variable console.log throws an error. This is because now the console.log statements are present in global scope where they have access to global variables but cannot access the local variables.