HTML Code Editor
Type or paste your HTML, CSS, and JavaScript code in the editor below. Toggle Live Preview to update the preview panel automatically as you type, or click Run to refresh it manually. Switch between side-by-side and stacked layouts using the layout buttons. In stacked mode, drag the handle between panes to resize the code editor height.
What Is an Online HTML Editor?
An online HTML editor is a browser-based tool that lets developers, designers, and learners write, edit, and instantly preview HTML, CSS, and JavaScript code without installing any software. The TechOreo Online HTML Editor provides a split-pane interface — a code editor on one side and a rendered live preview on the other — so changes are visible the moment you stop typing.
Unlike desktop editors such as VS Code or Sublime Text, an online HTML editor requires no installation, no local file system access, and no configuration. You open a browser tab, type code, and see the rendered result in under a second. It is ideal for learning web development, testing UI ideas, validating code snippets, debugging CSS issues, and quickly prototyping HTML layouts.
How to Use This HTML Editor
- Type or paste your HTML, CSS, and JavaScript code into the dark editor panel. Use the Tab key for 2-space indentation.
- With Live Preview enabled, the preview refreshes automatically 300ms after you stop typing.
- Click Run to manually refresh the preview at any time — useful when Live Preview is off.
- Click any Quick Template chip to load ready-made HTML snippets instantly.
- Use the layout toggle buttons to switch between side-by-side and stacked (below) views.
- In stacked mode, drag the resize handle between panes to adjust the code editor height. Double-click the handle to reset to 380px.
- Click Copy to send code to your clipboard, or Download to save as
page.html. - Use Format to auto-indent messy or pasted code for better readability.
- Click Fullscreen on the preview pane to view your output in a distraction-free overlay. Press Escape to exit.
Keyboard Shortcuts
| Shortcut | Action | Shortcut | Action |
|---|---|---|---|
Tab | Insert 2-space indent | Shift + Tab | Remove indent |
Ctrl + A | Select all code | Ctrl + Z | Undo last action |
Ctrl + C | Copy selected text | Escape | Exit fullscreen preview |
Key Features
Real-Time Live Preview
Preview refreshes automatically with a 300ms debounce after each keystroke, providing a smooth editing experience without excessive re-renders.
Side or Below Preview
Toggle between side-by-side layout (editor left, preview right) and stacked layout (preview below). In stacked mode the handle between panes is draggable.
Fullscreen Preview
Open your rendered HTML in a distraction-free fullscreen overlay. Press Escape or click Exit Fullscreen to return. Perfect for client demos.
Synchronized Line Numbers
Line numbers update in real time and scroll in sync with the code editor, making it easy to locate and debug specific lines.
7 Quick Templates
Load any of seven ready-made templates — Basic HTML, Contact Form, Data Table, Flexbox Cards, CSS Grid, CSS Animation, and Landing Page — with one click.
Code Auto-Formatter
One-click Format rebuilds your HTML with consistent 2-space indentation. Great for cleaning up pasted or minified code before reading or debugging.
Download as .html File
Save your work as a standalone page.html file. It opens correctly in any modern browser without an internet connection.
100% Private & Browser-Based
No code is ever sent to TechOreo's servers. The editor, formatter, preview, and download all execute locally in your browser.
Common Use Cases
Learning HTML, CSS & JavaScript
An online HTML editor is the fastest way for beginners to practise web development. Write a tag, see the result instantly, and iterate without any local setup. The Quick Templates also serve as practical starting points for understanding real-world HTML structure.
Rapid UI Prototyping
Designers and front-end developers use online HTML editors to sketch layouts, test colour combinations, and validate CSS flexbox or grid behaviour before writing production code. The fullscreen preview gives an accurate representation of how the page looks in a real browser tab.
Debugging and Isolating Code
When a bug is suspected in a specific HTML or CSS snippet, pasting it into a sandboxed editor helps isolate the problem from the wider codebase. The preview iframe executes code exactly as a browser would, including external CDN resources.
Testing HTML Email Templates
HTML emails use a restricted subset of HTML and inline CSS. The online editor lets you paste and preview email templates instantly, checking for layout breaks before sending through an email service provider.
Teaching & Live Demos
Teachers and presenters can write and demonstrate HTML concepts live with the audience seeing rendered output in real time alongside the code.
Interview Prep
Practise frontend coding challenges and see your solutions rendered instantly — no local environment required.
Supported Technologies
This editor fully supports HTML5, CSS3 (including animations, transitions, flexbox, and CSS grid), and JavaScript ES6+. You can also load external libraries and frameworks — such as Bootstrap, Tailwind CSS, jQuery, Alpine.js, or Chart.js — by including their CDN links in your <head> or <body> section. The preview iframe executes all valid HTML, CSS, and JavaScript exactly like a real browser tab.
The editor itself works in all modern browsers: Chrome 90+, Firefox 90+, Safari 14+, and Edge 90+. No browser extensions or plugins are required.
Tips for Best Results
- Always include
<!DOCTYPE html>and a complete<html>,<head>,<body>structure for accurate rendering. - Place
<style>tags inside<head>and<script>tags at the end of<body>for best practice performance. - Click Format immediately after pasting minified or messy code — it transforms unreadable markup into structured, indented HTML.
- Toggle Live Preview off when working on complex JavaScript, setInterval, or WebGL content; use Run for full manual control.
- In stacked layout, drag the resize handle downward to give the code editor maximum vertical space — especially helpful on laptops with long HTML files.
- Load the Landing Page or Flexbox Cards template and immediately customise the colours and text — the fastest way to prototype from scratch.
Frequently Asked Questions
<style> tags and JavaScript inside <script> tags. You can also load external frameworks like Bootstrap or Tailwind CSS by including their CDN links in the <head> section.
page.html file. It opens directly in any web browser and renders exactly as shown in the preview pane — no web server required.
<head> of your HTML. Bootstrap, Tailwind CSS (via Play CDN), jQuery, Alpine.js, Chart.js — all work inside the preview iframe exactly like a real browser tab.