Understanding var, let, and const in JavaScript: A Complete Beginner-Friendly Guide

Introduction to var in JavaScript In JavaScript, var is used to declare variables. It was the original way to create variables before let and const were introduced in ES6 (2015). Although still supported, var behaves differently from let and const. Understanding how it works is important, especially when reading older JavaScript code. Historical Background of var Before ES6, var was the only keyword available for declaring variables in JavaScript. Developers relied entirely on it to store and manage data in their programs. With the release of ES6, let and const were introduced to fix several limitations of var. Function Scope Behavior One of the most important characteristics of var is that it is function-scoped, not block-scoped. This means a variable declared with var inside a block (such as an if statement or loop) is still accessible outside that block, as long as it is within the same function. Example: if (true) { var message = "Hello"; } console.log(message); // "Hello" Hoisting