Semantic HTML Checker
Expose the div soup — missing landmarks, fake buttons, deprecated tags and loose images, scored instantly in your browser.
What this tool gives you
Check semantic markup
Paste a page or snippet. Analysis runs locally in your browser — nothing is sent anywhere.
Full pages or fragments work. The checker reads elements and attributes, not rendered pixels.
What this checker looks for
Semantic HTML is how machines understand your page. Screen readers, search crawlers and AI answer engines all parse the same tags.
Landmarks
main, header, footer, nav — jump targets for AT and structure for crawlers.
One h1
A single top-level heading anchors the page topic.
article / section
Self-contained regions are easier to quote and cite.
Real controls
button beats div+onclick for keyboard and screen-reader users.
No deprecated tags
font, center, marquee and align-based layout are 1990s markup.
Figures
Images wrapped in figure with figcaption keep captions attached.
How to use the checker
Paste the markup, then replace the meaning-free elements one region at a time.
Paste the markup
A whole page or a single fragment — the parser reads elements, not pixels.
Read the map
Landmarks, heading count, fake controls and deprecated tags are flagged per check.
Upgrade the structure
div to main/article, span+onclick to button, font/center to CSS.
What semantic structure needs
Every region should announce what it is — meaning in the markup beats meaning in a class name.
| Signal | Requirement | Why it matters |
|---|---|---|
| Core landmarks | main, header, footer present | Screen readers and crawlers navigate by regions, not by class names. |
| Single h1 | exactly one per page | One top-level heading anchors the topic for ranking and citation. |
| Content regions | article or section used | Self-contained blocks are the units AI engines quote. |
| Real controls | zero div+onclick | Buttons bring focus, Enter, Space and role with no extra code. |
| Modern markup | no font/center/marquee | Deprecated tags break styling isolation and confuse parsers. |
| Figures | images inside figure | A figcaption keeps the caption tied to the image it describes. |
Related GEO pages
Fix structure, then verify labels, headings and contrast.
Semantic HTML FAQs
What is semantic HTML?
HTML whose elements describe meaning, not just appearance: main, nav, article, button and figure tell screen readers and crawlers what each region is, while a stack of generic divs tells them nothing.
Does semantic HTML help SEO and AI visibility?
Yes. Landmarks and article regions make it easier for search engines and AI answer engines to extract the right block to rank or cite, and one clear h1 anchors the page topic.
Why are divs with onclick a problem?
A clickable div cannot be focused, does not respond to Enter or Space and has no button role. A real <button> gives all four for free, so keyboard and screen-reader users keep control.