[ LANGUAGE — NODE 24 ]
Run JavaScript online. No install.
Run JavaScript online with Node. Test snippets, practice algorithms and debug without local setup.
Sample — copy into the compiler
const name = "CodeLab";
console.log(`Hello, ${name}!`);
const total = Array.from({ length: 100 }, (_, i) => i + 1)
.reduce((a, b) => a + b, 0);
console.log("Sum 1..100 =", total);1. Open the JavaScript runtime
Go to the compiler and select JavaScript. Your code persists per language.
2. Paste and add input
Copy the sample or type your own. Fill stdin if the program reads input.
3. Run and share
Press Run in the editor, then copy the page URL to share your exact state.
JavaScript FAQ
Do I need to install JavaScript to use this?
No. The Node 24 runtime runs in your browser via CodeLab's embedded editor. Open the compiler, pick JavaScript, and press Run.
Is running JavaScript online free?
Yes. The CodeLab Playground is free with no account. Optional paid plans add privacy and larger limits — see the pricing page.
How do I handle input in JavaScript?
Use the stdin panel inside the editor for piped input, then press Run. The sample below reads a name from stdin.