HTML Viewer
Free online tool for real-time HTML code preview. Features syntax highlighting, HTML validation, and responsive preview. No development environment needed - just use your browser.
What is HTML Viewer?
HTML Viewer is a free online tool that lets you preview HTML code in real-time. Enter your code and instantly see the results, with syntax highlighting, HTML validation, and responsive preview features.
It’s perfect for web developers, designers, and learners who want to quickly test HTML and CSS code and see the results. No need to set up a separate development environment – just use your browser.
Who Is This For?
- Web Developers – Quickly test and verify HTML snippets
- Frontend Designers – Real-time preview of CSS styles
- Coding Students – Learning and experimenting with HTML/CSS
- Bloggers/Content Creators – Preview HTML widgets and code snippets
- Team Collaboration – Quick verification during code reviews
Key Features
- Real-time Preview – Code is reflected in the preview immediately as you type.
- Syntax Highlighting – HTML, CSS, and JavaScript code is displayed with color coding.
- HTML Validation – Detects issues like unclosed tags and deprecated tags.
- Responsive Preview – Simulate desktop, tablet, and mobile screen sizes.
- External Resources – Add CDN resources like Bootstrap, Tailwind, etc.
- Sample Code – Provides samples like basic HTML, cards, forms, and animations.
- Auto-save – Your working code is automatically saved in the browser.
- Copy & Download – Copy code to clipboard or download as an HTML file.
- Fullscreen Preview – View results in full screen.
HTML Validation Items
This tool detects the following HTML issues:
- DOCTYPE Declaration – Warns if <!DOCTYPE html> declaration is missing.
- Unclosed Tags – Shows errors for missing closing tags like <div>, <p>.
- No Matching Tag – Shows errors for closing tags without opening tags.
- Deprecated Tags – Warns about obsolete tags like <font>, <center>.
- Accessibility – Warns when <img> tags are missing alt attributes.
How to Use
- Enter HTML code in the editor.
- The preview updates in real-time as you type.
- Check errors and warnings in the validation section.
- Test various screen sizes with the responsive buttons.
- When done, use the copy or download button.
Using External Resources
Click the “External” button to add external CSS or JS files:
- Bootstrap – https://cdn.jsdelivr.net/npm/bootstrap@5/dist/css/bootstrap.min.css
- Tailwind – https://cdn.tailwindcss.com
- Font Awesome – https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0/css/all.min.css
Paste the URL in the input field and it will be automatically applied to the preview.
Sample Code Descriptions
- Basic HTML – Example of basic HTML document structure and styling
- Card Layout – Responsive card layout using CSS Grid
- Form Design – Modern styled contact form
- Animation – CSS animations (bounce, fade-in, spinner)
Important Notes
- Entered code is saved in your browser’s localStorage and is not sent to any server.
- JavaScript execution is sandboxed within an iframe, but avoid running untrusted code.
- Preview is rendered in your current browser environment and may differ in other browsers.
- Processing large amounts of code may impact performance.