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Valid HTML Statistics

This page shows trends for web standards compliance across sites submitted to this service.

Valid HTML / XHTML Pages

Graph: about 35% of pages checked are valid HTML

Percentage of pages that validate against DOCTYPE.

Graph: over 30% of pages marked as valid HTML are actually invalid

Percentage of pages marked as "Valid HTML" or "Valid XHTML" that don't validate against DOCTYPE.

What is a DOCTYPE?

A Document Type Declaration, or DOCTYPE, is a piece of HTML code that says which version of HTML is being used. For example:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">

Note: Data is anonymized and aggregated to show averages. No site specific data is ever shown.