Making a page respond
HTML gives a page its content, and CSS sets its appearance. JavaScript can change what you see as you use the page. For example, clicking “Add to basket” can make the item count increase without reloading the whole page. JavaScript can also check a form or load new information.
Beyond the browser
JavaScript can also run on servers and in other software. Despite their similar names, JavaScript and Java are different programming languages. Tools such as Node.js and Deno provide environments for running JavaScript outside a browser. TypeScript adds checks to JavaScript during development.