HTML Validator
Validate HTML syntax and detect errors like unclosed tags, missing attributes, and structural issues. Find problems before deployment.
How to Validate HTML
Step 1: Paste Your HTML
Enter or paste your HTML code. Click "Sample" to see a valid example.
Step 2: Click Validate HTML
The validator checks for common HTML errors and issues.
Step 3: Review Results
See if your HTML is valid or if there are errors and warnings to fix.
Step 4: Fix Issues
Address any errors (unclosed tags, missing attributes) and warnings (accessibility, structure).
Step 5: Revalidate
Run validation again to ensure all issues are resolved.
Frequently Asked Questions
What does HTML validation check?
It checks for unclosed tags, missing required attributes, structural issues, and accessibility problems.
What's the difference between errors and warnings?
Errors are critical problems that break HTML structure. Warnings are best practice recommendations.
Why is DOCTYPE important?
DOCTYPE tells browsers how to render the page. Missing DOCTYPE can cause rendering issues.
Why do images need alt attributes?
Alt attributes are important for accessibility and SEO. They describe images for screen readers and when images don't load.
What are self-closing tags?
Self-closing tags like <br />, <img /> don't need closing tags. They complete themselves.
Can invalid HTML still work?
Browsers are forgiving and often render invalid HTML anyway. But errors can cause unexpected behavior.
Should I fix all warnings?
Always fix errors. Warnings are recommendations. Fix them to follow best practices and improve accessibility.
Does validation check CSS and JavaScript?
No, this tool only validates HTML structure. Use separate tools for CSS and JavaScript validation.
Is this validator complete?
This checks common HTML issues. For comprehensive validation, use W3C HTML Validator or your IDE's validator.
Is my code private?
Yes, all validation happens in your browser. Your HTML is never sent to any server.
About HTML Validation
HTML validation is essential for web development quality:
- Error Prevention: Catch mistakes before deployment
- Consistency: Ensure code follows HTML standards
- Accessibility: Find accessibility issues early
- Browser Compatibility: Reduce cross-browser issues
- SEO Improvement: Valid HTML is better for search engines
- Performance: Valid code renders faster
- Maintenance: Valid code is easier to maintain
- Professional Standard: Validation is part of best practices