Variables: var, let & const — Free JavaScript Tutorial

Learn Variables: var, let & const in JavaScript with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

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TL;DR: Learn Variables: var, let & const in JavaScript with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Sep 17, 2026

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Variables: var, let & const in JavaScript

JavaScript has 3 ways to declare variables: var (old, function-scoped, avoid), let (modern, block-scoped, can be reassigned), and const (modern, block-scoped, cannot be reassigned). Always prefer const, then let.

JavaScript data types: String, Number, Boolean, null, undefined, Object, Array, Function. Use typeof to check a variable's type.

Template literals (backticks \

Variables: var, let & const — Syntax

const name = "Arjun";    // can't change
let age = 17;           // can change
var old = "avoid this"; // old style

typeof age   // → "number"
\

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