JS Tutorial

JavaScript Scope 🎯

Scope determines the accessibility (visibility) of variables. In JavaScript, there are different types of scope:

• Global Scope
• Function Scope
• Block Scope (with let and const)

🌍 Global Scope

Variables declared outside any function are in the global scope and accessible anywhere in the code.

let globalVar = "Hello";

function sayHello() {
  console.log(globalVar); // Accessible here
}

🔁 Function Scope

Variables declared inside a function are only accessible within that function.

function testScope() {
  let localVar = "I am local";
  console.log(localVar); // Works
}

console.log(localVar); // ❌ Error: not defined

📦 Block Scope (let & const)

Variables declared with let or const inside { } are limited to that block.

{
  let blockVar = "Inside block";
  console.log(blockVar); // ✅ Works
}
console.log(blockVar); // ❌ Error

🧪 Live Scope Tester

💡 Scope Summary

• var is function-scoped, not block-scoped.
• let and const are block-scoped.
• Global variables are accessible anywhere, but use with care!