How to use the Heading Structure Checker
- Paste HTML.
- Run the checker.
- Review heading counts and hierarchy warnings.
Frequently Asked Questions
Does it fetch a URL?
No, browser security prevents arbitrary cross-origin page fetching. Paste the HTML instead.
Are findings deterministic?
Yes.
Why heading structure matters
One clear H1, followed by H2 sections and H3 subsections, helps readers scan a page and helps assistive technology navigate it. Skipping levels, such as jumping from H1 to H4, makes the outline confusing.
Paste your page HTML to see the outline. Fix missing or duplicate H1 tags first, then check that each section's heading describes its content.