var

var is a keyword in JavaScript used to declare variables with function scope or global scope, depending on where it is defined. It was the primary way to declare variables in JavaScript before ES6 (ECMAScript 2015) introduced let and const. Variables declared with var are hoisted to the top of their scope, meaning they can be accessed before their declaration in code.

Also known as: variable declaration, var keyword, JavaScript var, ES5 var, var statement

Why learn var?

Developers should learn var to understand legacy JavaScript code and maintain older projects where it is commonly used. It is essential for grasping JavaScript's scoping rules and hoisting behavior, which helps in debugging and writing predictable code. However, in modern development, let and const are preferred for block scoping and avoiding hoisting issues.

Learning Resources

• docs: MDN Web Docs: var
• tutorial: JavaScript.info: Variables
• tutorial: freeCodeCamp: var vs let vs const
• tutorial: W3Schools: JavaScript var