Doctype checker
Doctype checker detects the document type declaration in fetched HTML. Review whether a page reports a doctype before investigating markup and rendering issues.
Doctype checker: what this tool checks
Doctype checker looks for a document type declaration in the HTML returned by a URL. The declaration sits outside the main page content and identifies a document type to the parser. Checking it can help during template migrations, troubleshooting inconsistent pages, or reviewing documents produced by a publishing system.
How to use it
- Enter the page address in the URL field.
- Submit the request and inspect the doctype name in the result.
- If it is missing or unexpected, review the beginning of the original response and the template that generates it.
Understanding your results
A found result shows the parsed doctype name. This is a narrow presence check. It does not validate all HTML, identify every legacy declaration detail, or test the rendering mode of an actual browser. A parser may also normalize imperfect markup while reading a document.
Frequently asked questions
Does a found doctype mean the HTML is valid?
No. Invalid nesting, duplicate attributes, and obsolete markup can still exist in a document with a doctype. Use a dedicated HTML validator for a full conformance review.
Why check individual templates?
A normal landing page, an error page, and a generated report may have different wrappers. Testing each relevant template helps locate a problem that would be missed by checking only the homepage.
Continue your review
Continue with the Deprecated HTML tags checker, examine declaration consistency using the Meta charset checker, and compare document structure through the DOM size checker.
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