Pull out your phone or open your laptop and visit almost any website. YouTube. Gmail. Your bank. Your favorite online shop. A news site.
Now try a few things:
- Click a "like" button and watch the heart turn red instantly, without the page reloading.
- Start typing in a search box and watch suggestions appear as you type.
- Drag a map around with your mouse.
- Type a password that's too short and see a little red warning pop up: "Password must be at least 8 characters."
- Add something to your shopping cart and watch the little number on the cart icon go up.
Every single one of those things is powered by JavaScript.
JavaScript (often shortened to JS) is the programming language of the web. It's built into every major web browser on the planet: Chrome, Firefox, Safari, Edge, all of them. That means every computer and smartphone with a web browser can already run JavaScript. You don't need to install anything special to get started. You already have everything you need.
Pretty cool, right?