# JavaScript JavaScript allows you to add interactivity to your pages. Common examples that you may have seen on the websites are sliders, click interactions, popups and so on. Apart from being used on the frontend in browsers, there is Node.js which is an open-source, cross-platform, back-end JavaScript runtime environment that runs on the V8 engine and executes JavaScript code outside a web browser. Free Content W3Schools – JavaScript Tutorial The Modern JavaScript Tutorial Codecademy - Learn JavaScript JavaScript Crash Course for Beginners Node.js Crash Course Node.js Tutorial for Beginners