Learn JAVASCRIPT with Real Code Examples

JavaScript allows developers to control the behavior of web pages.

It supports object-oriented, functional, and event-driven programming paradigms.

Works alongside HTML for structure and CSS for styling.

First-class functions and closures

DOM and BOM (Browser Object Model) access

Cross-platform execution in browsers and servers

JSON support for data interchange

Modules for code organization

Variables: `var`, `let`, `const`

Data types: string, number, boolean, object, array, null, undefined

Functions: declaration, expression, arrow functions

Control structures: if, for, while, switch

Events: click, input, load, DOMContentLoaded

index.html - main page

js/main.js - primary JavaScript file

js/modules/ - reusable modules

assets/ - images, fonts, media

package.json - Node.js project configuration

Write JavaScript code in `.js` files

Link JavaScript to HTML via `<script>`

Test code in browser console or Node.js

Debug using developer tools

Optimize and modularize code using modules

Beginner: DOM manipulation and event handling

Intermediate: form validation, local storage

Advanced: SPA frameworks (React, Vue, Angular)

Expert: Node.js backend, asynchronous patterns

Community: contributing to JS libraries and standards

More dynamic than HTML/CSS alone

Runs client-side unlike server-side languages like PHP

Complementary with frameworks for SPA

Event-driven unlike static languages

Versatile for full-stack development

1995 – Initial release in Netscape Navigator

1997 – ECMAScript 1 standardized

2009 – ECMAScript 5 introduced strict mode

2015 – ECMAScript 6 (ES6/ES2015) with major features

2025 – ECMAScript continues evolving with yearly updates

DOM: Document Object Model

Event Loop: mechanism handling asynchronous callbacks

Closure: function retaining access to outer scope variables

Promise: object representing future completion of async task

Callback: function passed as argument to be executed later