Document missing doctype

Specifying a doctype prevents the browser from switching to quirks-mode. Lighthouse flags your page when it's missing <!DOCTYPE html>:

Lighthouse audit showing missing doctype
Document missing doctype.

How to pass this audit

To pass this audit, add <!DOCTYPE html>.

Learn more in Doctype.

Each Best Practices audit is weighted equally in the Lighthouse Best Practices Score. Learn more in The Best Practices score.

More information

Document missing doctype audit source

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