Why this tool is useful
Use HTML Landmark Checker when you need to inspect pasted HTML for main, navigation, banner, complementary and footer landmarks with naming warnings. The result is immediate and easy to verify before you reuse it.

inspect pasted HTML for main, navigation, banner, complementary and footer landmarks with naming warnings.
Ready. Your working data stays in this browser.
Use HTML Landmark Checker when you need to inspect pasted HTML for main, navigation, banner, complementary and footer landmarks with naming warnings. The result is immediate and easy to verify before you reuse it.
Enter the values requested by HTML Landmark Checker. The browser validates the input, performs the calculation locally and produces a copyable result with clear errors.
A practical use is to run HTML Landmark Checker on a small sample first, confirm the output, and then process the complete value or list.
The calculation is deterministic and explains validation errors instead of silently changing invalid input.
Input and output remain in this tab. Copy and download happen through browser APIs without a server upload.
Every run reports its tool mode, timestamp and input/output size so transformed data can be audited.