Modern ECMAScript on Node.js · no installation required

JavaScript Playground Online

Write and run JavaScript code instantly in your browser. No installation needed. Practice ES6+, arrays, async/await, DOM events, and modern JavaScript patterns with immediate feedback.

Open the JavaScript playground

A small JavaScript starter

Review this deterministic example, then open it in the full sandbox when you are ready to edit and run code.

const topics = ["arrays", "async", "objects"];
console.log("Practice " + topics.length + " topics");

Expected output

Practice 3 topics

Common uses

  • Practice array transformations
  • Test async patterns
  • Explore language syntax

Know the limits

Code runs as a small Node.js program, not inside a browser page. DOM APIs, installed packages, and persistent files are not available.

Continue with JavaScript lessons

Turn a quick experiment into structured practice with these course lessons.