HTML & CSS Version Checker

Free
Utility

Analyze your website's HTML and CSS versions, feature support, and compatibility with modern web standards.

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Understanding Web Standards

Modern web development relies on following established standards to ensure compatibility, accessibility, and performance.

HTML Standards

HTML5

The current standard with rich semantic elements and multimedia support

Semantic Elements

Improve accessibility and SEO with meaningful structure

Form Features

Modern input types and validation for better user experience

CSS Features

Modern Layout

Flexbox and Grid for responsive designs

Animations & Transitions

Smooth visual effects for better interactivity

Custom Properties

Variables for maintainable styling

Best Practices

  • Keep your DOCTYPE declaration current
  • Use semantic HTML elements appropriately
  • Implement modern CSS features when possible
  • Include proper meta tags for SEO
  • Test across different browsers

Browser Support

Modern features are well-supported across current browsers. However, if you need to support older browsers, consider:

  • Progressive enhancement strategies
  • Fallback styles for older browsers
  • Feature detection using @supports
  • Polyfills for critical features
01

Comprehensive Analysis

Analyze your website's compatibility with modern web standards and features.

HTML Version Detection

Detect HTML version and doctype with semantic element analysis.

CSS Analysis

Analyze CSS versions and modern feature usage across stylesheets.

Feature Support

Check for modern web features and browser compatibility.

Deep Analysis

Comprehensive scanning of external resources and dependencies.

Issue Detection

Identify potential compatibility issues and outdated features.

Meta Information

Extract and analyze meta tags and document structure.

6+
Features
99.9%
Reliability
24/7
Available
Free
Always
02

How to Use

Simple 4-step process

1

Step 1

Enter the website URL you want to analyze

2

Step 2

Get detailed analysis of HTML and CSS versions

3

Step 3

Review feature support and compatibility

4

Step 4

Get recommendations for improvements

Quick Start
Begin in seconds
Easy Process
No learning curve
Instant Results
Get results immediately

Version Checker FAQ

Everything you need to know about our process, pricing, and technical capabilities.

See Full FAQ

Checking HTML and CSS versions is important for: Ensuring browser compatibility Identifying modernization opportunities Maintaining web standards compliance Optimizing performance Planning updates and improvements

Our tool analyzes multiple aspects: HTML version and doctype Semantic HTML elements CSS version and features Modern CSS properties Meta tags and structure Multimedia elements

The results show: Current HTML/CSS versions in use Support for modern features Potential compatibility issues Recommendations for improvements Green indicators show modern features, while yellow or red indicate areas for improvement.

Consider updates when you see: Older HTML versions (pre-HTML5) Limited CSS feature usage Missing semantic elements Deprecated features Focus on areas that impact user experience and maintainability.

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