Description
HTML & CSS W3C Validator Pro
Ensure your code meets World Wide Web Consortium (W3C) standards with a single click.
Developing clean, standards-compliant websites is essential for SEO, accessibility, and cross-browser compatibility. This extension streamlines the debugging process by sending your page's code directly to the official W3C Validators, eliminating the need for manual copy-pasting.
Unlike basic tools, this extension is built for the modern web: it handles dynamic DOM states, external frameworks, and complex stylesheets effortlessly.
π KEY FEATURES
Advanced HTML5 Validation: Captures the current state of your DOM, including elements generated dynamically by JavaScript.
Smart CSS Validation (Pro): Overcomes CORS restrictions to analyze stylesheets that standard validators often miss.
Merge & Validate: Automatically fetches all internal and external styles (including CDNs like Bootstrap or Tailwind), merging them into a single block for a complete audit.
Used CSS Analysis: Focus on efficiency by extracting and validating only the rules currently affecting elements on your page.
Source Validation: Ideal for checking raw .css files or the direct page source in the browser.
π¨βπ» DEVELOPER-CENTRIC WORKFLOW
Official Standards: Direct integration with validator.w3.org and jigsaw.w3.org.
Visual Feedback: Provides immediate status indications and cursor updates while processing complex data.
Privacy-Focused: Built on Manifest V3 with no tracking or ads; your code is only sent to W3C servers for analysis.
Secure Execution: Utilizes safe fetching methods to protect user privacy while retrieving external assets.
π― IDEAL FOR
Web Developers: Identify unclosed tags, invalid attributes, and CSS syntax errors during production.
SEO Specialists: Ensure semantic markup is valid to improve search engine crawling.
Accessibility Experts: Verify code structure to maintain compatibility with screen readers.
QA Testers: Streamline technical audits for complex, framework-heavy applications.
Start writing higher-quality code today. Install HTML & CSS W3C Validator Pro.
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Permissions (2)
Permissions
activeTabβΉ Can access the current tab when you click the extension scriptingβΉ Can inject scripts into web pages
Details
| Version | 1.4 |
| Updated | Feb 8, 2026 |
| Size | 43.04KiB |
| First Seen | Mar 24, 2026 |
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