write it, run it, read the output — no setup, no tab switching
⌘/Ctrl + Enter to run
Code
Output
console.log output shows up here.
Runs on a worker thread inside a sandboxed frame — no access to the page, cookies or storage, and anything still going after 4 seconds is killed, so an infinite loop costs you a moment rather than the tab. There is no document or DOM in here; it is for JavaScript and DSA practice. Nothing is saved — copy out what you want to keep.