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HTML Preview / Live Code Editor

Last updated: July 11, 2026

Write HTML, CSS, and JavaScript code and see a live preview instantly. Perfect for testing snippets, prototyping layouts, and learning web development without needing a local setup.

How to Use This HTML Preview

  1. Write or paste your HTML code in the HTML tab.
  2. Optionally switch to the CSS or JavaScript tabs to add styles and scripts.
  3. Click "Run & Preview" to render your code in the live preview iframe.
  4. The preview updates only when you click the button, so you can edit freely before running.

How It Works

The preview combines your HTML, CSS, and JavaScript into a single document rendered inside a sandboxed iframe. CSS is injected via a <style> tag, and JavaScript runs after the DOM loads.

The iframe uses the sandbox="allow-scripts" attribute for security, preventing scripts from accessing the parent page. All code runs entirely in your browser—nothing is sent to any server.

Examples

Example 1: Simple Page

<h1 style="color:blue">Hello World</h1> <p>This is a live preview.</p>

Example 2: Styled Card

HTML: <div class="card"><h2>Card Title</h2><p>Card content</p></div>
CSS: .card { padding: 20px; border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.1); }

Example 3: Interactive Button

HTML: <button onclick="alert('Clicked!')">Click Me</button>
JS: Works directly in the preview with the sandbox attribute.

Frequently Asked Questions

What is an HTML preview tool?

An HTML preview tool lets you write and edit HTML, CSS, and JavaScript code in a text editor and see the rendered result in real time within your browser. It’s like having a mini code editor and browser combined, useful for learning and prototyping.

What are the use cases?

Common use cases include: learning HTML/CSS/JS basics, testing code snippets before adding to a project, prototyping email templates, debugging layout issues, sharing code demos with others, and quick UI mockups without setting up a development environment.

Is my code sent to a server?

No. All code rendering happens locally in your browser using a sandboxed iframe. Your code never leaves your device, making it safe for testing any HTML, CSS, or JavaScript.

Disclaimer: This tool runs code locally in your browser using a sandboxed iframe. Do not paste untrusted third-party code. The sandbox limits external resource loading for your security.

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