Javascript-Scope:

There are two types of scope in JavaScript:

Global scope
Local scope

Global Scope:

Javascript Variables declared outside of any function become global variables and Global variables can be accessed and modified from any function.

Example: Global Variable

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Scope</h2>

<p>A GLOBAL variable can be accessed from any script or function.</p>

<p id="global"></p>

<script>
var tutorialName = "i2tutorials";
myFunction();

function myFunction() {
 document.getElementById("global").innerHTML = "I can display " + tutorialName;
}
</script>

</body>
</html>

OUTPUT:

JavaScript Scope

A GLOBAL variable can be accessed from any script or function.

I can display i2tutorials

Local Scope:

Javascript Variables declared inside any function with var keyword are called local variables. Local variables can’t be accessed or modified outside the function declaration.

Example: Local Scope

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Scope</h2>

<p>Outside myFunction() tutorialName is undefined.</p>

<p id="demo1"></p>

<p id="demo2"></p>

<script>
myFunction();

function myFunction() {
 var tutorialName = "i2tutorials";
 document.getElementById("demo1").innerHTML = typeof tutorialName + " " + tutorialName;
}
document.getElementById("demo2").innerHTML = typeof tutorialName;
</script>

</body>
</html>

OUTPUT:

JavaScript Scope

Outside myFunction() tutorialName is undefined.

string i2tutorials

undefined