Markup validity
Captures unclosed tags, conflicting ids, invalid attributes, and incorrect nesting. Each issue includes its location and effect.
Online HTML code check
Check your site’s HTML online. Find markup errors, missing image descriptions and SEO tag issues to prepare fixes.
How it works
We check HTML so it is clear what to fix next
Enter a page URL. Milten opens it in a browser and validates the captured HTML. The DOM, the page's element tree, helps connect a finding to a template or component.
- 01 · URL
Capture the final page markup
The scanner opens the URL, waits for the base render, and captures the HTML the user actually gets: server markup, CMS templates, and elements added by scripts.
- 02 · DOM
Find structural problems
Validate HTML and inspect the element tree: nesting depth, duplicate IDs and tag groups. A large element count needs investigation but does not prove a defect on its own.
- 03 · REPORT
Build a fix plan
For example, two elements have the same ID. Locate both in the template, assign unique IDs and update related labels and links. Rerun validation and test the page after changing them.
Analysis modules
What goes into the HTML report
Each module answers a practical question: where markup became heavy, what blocks indexing, and which fixes should be sent to developers first.
Technical SEO signals
Checks title, description, canonical, robots, hreflang, Open Graph, and structured data. The report notes what affects snippets and indexing.
HTML weight by category
Breaks the file into content, components, inline CSS/JS, SVG, and comments. This makes it easier to find the source of extra kilobytes and remove it precisely.
DOM structure
Shows tree depth, node count, repeated branches, and empty wrappers. The report makes it clear which blocks can be simplified without changing the design.
Semantics and accessibility
Checks landmarks, heading order, alt text, form labels, ARIA, and keyboard access so the page is understandable to people and search engines.
Duplicates and technical clutter
Finds repeated meta tags, extra canonical/hreflang links, empty div/span elements, and hidden nodes. Recommendations explain what to keep and what to remove.
FAQ
Frequently asked questions about HTML analysis
Short answers about DOM, validity, HTML size, SEO, and accessibility.
How is HTML Scanner different from a speed check?
Speed Scanner looks at Core Web Vitals, and loading resources. HTML Scanner focuses on markup itself: DOM tree, HTML weight, validity, semantics, accessibility, and technical SEO tags.
Can I check just one page?
Yes. The form accepts the URL of a specific page: homepage, landing page, catalog, product page, or article. For templated sites, it is usually useful to check one page of each type.
Why can large HTML be a problem?
Heavy HTML takes longer to transfer, parse, and maintain. Common causes include inline scripts, large SVGs, repeated cards, extra wrapper layers, CMS comments, and data that should be loaded separately.
Does the scanner show accessibility errors?
Yes, within HTML analysis: form labels, alt text, landmark areas, heading hierarchy, ARIA conflicts, and elements missing semantic roles. A full a11y audit can be a separate step.
What should I do with validator errors?
Start with P1: duplicate ids, incorrect nesting of interactive elements, unclosed tags, conflicting meta/canonical tags, and form issues. After that, clean extra wrappers and improve semantics.
Related services
What to check next to this service
CSS audit
Find large stylesheets, duplicates, and styles unused during loading. Unused styles may still be needed on other pages or after user actions.
OpenAccessibility
Find accessibility issues with an automated check. Get recommendations; a full accessibility assessment also needs manual checks.
OpenSEO audit
Audit up to 5 pages for SEO, metadata and content availability before and after JavaScript.
OpenAI agent website audit: content and access
Check page content, structure and public access settings for AI agents. Find technical obstacles without predicting citations or inclusion in AI answers.
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