Script Runner
Run JavaScript & see output
Script Runner: Run JavaScript & see output. A free, browser-based tool from DevToolbox that runs entirely on your own device: no upload, no account, no tracking.
About the Script Runner
Free online JavaScript runner. Write and execute JavaScript code in your browser with console output, error handling, and execution time. No server required. It is one of the testing & analysis tools on DevToolbox, and like all of them it runs entirely in your browser.
The analysis runs against your input as you type, so you see the effect of a change immediately rather than after a submit. Everything is computed in the browser, which is why large inputs stay responsive. There is no request latency between you and the result.
What you can do with it
- JavaScript runner
- JS runner online
- Run JavaScript online
- JavaScript sandbox
- JS executor
How to use it
- Paste the text or data you want to examine.
- Adjust the pattern, options or comparison to suit what you are looking for.
- Results update live as you change either side.
- Copy what you need, or share a link that carries the input with it.
Questions
- Is my data uploaded anywhere?
- No. The tool is JavaScript that runs in the tab you already have open, and DevToolbox has no backend to send anything to. You can open the network tab and watch: after the page and its script load, nothing is sent while you work.
- Does it work offline?
- Once the page has loaded, yes. The tool needs no network access to do its job, so it keeps working if your connection drops. Reloading the page does need the network unless your browser has it cached.
- Is it free, and do I need an account?
- It is free and there is no account, no sign-in and no usage limit. There is nothing to register because there is no server keeping track of anything.
Related tools
The Script Runner sits in Testing & Analysis, one of the 90 tools on DevToolbox.