Doctype and the basics of a valid document
Best practices1 min readFixes check doctype
A missing doctype throws browsers into quirks mode with 1990s layout rules. Start every page with <!doctype html>.
Step by step, with screenshots: HTML validation errors: which ones matter and which are noise →
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What a passing site looks like
- Doctype is presentwarning · −1 ptseffort S
Doctype is missing
Why it matters. Without <!doctype html>, browsers render in quirks mode and layouts can differ between browsers.
How to fix it.
- Put <!doctype html> as the very first line of the document.