JavaScript Variables: var, let, and const In JavaScript, variables are fundamental components of data storage and manipulation. data. With the introduction of let and const in ES6 (ECMAScript 2015), JavaScript developers gained more control and flexibility in how variables are defined and used. This guide will cover var , let , and const in detail, providing examples, use cases, and best practices. Variables are data containers used to store information in memory. When declared using var , let , or const , a memory location is reserved for the variable. The let keyword is used for variables whose values may change, while const is for values that remain constant, like PI or gravity . Avoid using var as it is error-prone. JavaScript variable naming rules: Must not start with a number. Special characters are not permitted in javascript, we can use $ and _. Follows camelCase convention. Should not include spaces between words. Var in Javascript 1. var Variable var allows you ...