💡 JavaScript
Output
Press Run to see output…
Ctrl+Enter to run · Code runs in a sandboxed iframe · Your code is never sent to a server
Try these examples
Click any example to load it into the editor above, then hit Run.
How this works
Your code runs entirely in your browser — nothing is sent to a server. The playground intercepts console.log, console.error, and console.warn, then displays the output below the editor. Errors are caught and shown in red.
The sandbox supports all modern JavaScript: ES2015+ syntax, async/await, classes, modules syntax (as expressions), and the full standard library. It does not have access to Node.js APIs (fs, http, etc.) or the DOM beyond what the page itself exposes.
What to try next
- JavaScript Foundations track — structured lessons from first principles
- JavaScript snippets — 15 copy-ready idiomatic patterns
- JavaScript language reference — deep dives on closures, async, and the type system
- To-Do List project in JS — first real program to build