What is it?
The HTML, CSS and JS Playground has three boxes for HTML, CSS and JavaScript and a Live preview that updates as you type. Your code runs in a sealed-off frame: it cannot read this site or your other tabs. Work is saved on this device as you type.
Who is it for?
Students learning web design, Blogger owners testing a widget before adding it, developers trying a quick idea, and teachers demonstrating HTML and CSS in class.
How to use it
- Type or paste into the HTML, CSS and JavaScript boxes.
- Watch the preview; tap Run ▶ to restart scripts.
- Download .html saves everything as one file; Clear starts fresh.
Example
HTML <button id="b">Tap</button>, CSS #b{padding:12px;border-radius:8px}, JS b.onclick=()=>alert('Hi'): the preview shows a rounded button that greets you.
Errors and how to fix them
- Preview blank: an HTML tag isn’t closed or the JavaScript has an error; check the browser console or comment out parts.
- External scripts or fonts don’t load: some sites block loading inside frames; download the file and open it directly.
- Work disappeared: it’s saved in this browser only; private windows and cleared data lose it. Download important work.
Questions people ask
- Can I use libraries? Add a script tag from a CDN in the HTML box.
- Can I share my work? Download the .html file and send it.
Open the tool: HTML, CSS and JS Playground
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.