Online HTML Editor
Write HTML, CSS, and JavaScript with real-time live preview
Live Preview
About This HTML Editor
Our free online HTML editor lets you write HTML, CSS, and JavaScript code and see the results instantly in a live preview. Perfect for learning web development, testing code snippets, or quickly prototyping ideas.
Key Features
- Live Preview - See your changes instantly as you type
- Separate Panels - Write HTML, CSS, and JavaScript in dedicated editors
- Console Output - View console.log output without opening browser DevTools
- Export to HTML - Download your creation as a standalone HTML file
- Share Your Code - Create shareable links to your code snippets
- No Signup Required - Start coding immediately, no account needed
Use Cases
- Learning HTML/CSS/JS - Practice web development fundamentals
- Quick Prototypes - Test ideas before adding to your project
- Code Snippets - Share working examples with teammates
- Bug Reproduction - Create minimal reproductions for debugging
- Teaching - Demonstrate concepts with live, editable examples
Tips
- Use
console.log()in your JavaScript to see output in the Console panel - The preview runs in a sandboxed iframe for security
- Press Tab in the editor to insert spaces for indentation
- Click "Load Sample" to see an example project
How the Live Preview Works
The three editors are just separate text areas for your HTML, CSS, and JavaScript. Every time you type, the tool stitches them into a single HTML document and hands that document to an <iframe> through its srcdoc attribute: your CSS is wrapped in a <style> block in the head and your script is placed just before the closing body tag, exactly as a real page would be. The update is debounced by a fraction of a second so the preview stays responsive while you type instead of re-rendering on every keystroke. All of this happens locally in your browser; your code is never sent to a server.
To surface errors and logs without opening browser DevTools, the editor injects a small script that wraps console.log, console.warn, and console.error and forwards their messages to the Console panel below the preview. A window.onerror handler catches uncaught exceptions too, so a typo in your JavaScript shows up as a red line rather than silently failing.
About the Sandbox
The preview iframe carries a sandbox="allow-scripts allow-same-origin" attribute. allow-scripts is what lets your JavaScript run at all, while the sandbox still blocks things like top-level navigation and form submission from affecting the page around it. This is why the editor is a safe place to paste and run unfamiliar snippets: the code executes in an isolated frame rather than in the context of the whole site. Note that because scripts are enabled, you should still only run code you understand: the sandbox contains the preview, it does not vet what your code does inside it.
Frequently Asked Questions
Does my code get uploaded anywhere?
No. The editor assembles your HTML, CSS, and JavaScript into a document and renders it in an in-page iframe entirely within your browser. Nothing is sent to a server unless you deliberately create a share link, which encodes the code into the URL.
Why can I see console.log output without opening DevTools?
The tool injects a small wrapper around console.log, console.warn, and console.error inside the preview and forwards their messages to the Console panel. Uncaught errors are captured through a window.onerror handler, so mistakes appear as red lines in that panel.
Can I load external libraries or images?
Yes. Because the preview is real HTML, you can add a script or link tag pointing at a CDN, or reference an image by its full URL, and it will load as it would on any web page. Relative paths will not resolve, since there is no hosting folder behind the preview.
How do I save my work?
Use "Export HTML" to download everything as a single standalone .html file you can open or host anywhere, or use the share button to generate a link that reconstructs the exact HTML, CSS, and JavaScript when opened. The editor does not keep your work after you close the tab.
What does the Pan mode do?
Pan mode renders the preview at a fixed 1920x1080 canvas and lets you drag or scroll around it, similar to moving around a design in Figma. It is useful for inspecting how a wide desktop layout looks without shrinking it to fit the panel.
Discussion
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