WP-Validate indexes your site, collecting all the blog posts, pages and other published content, and submits it to the W3C’s HTML Validator, which then returns the response.
WP-Validate then lists the valid pages, and the invalid pages, with a link to the specific validator URL.

WP-Validate

WP-Validate collects all the pages on your site and runs them through the W3C's HTML Validator.

tammax

Automatically checks the validity of the page with the service provided by the site http://validator.w3.org/
Verifica in automatico la validit? della pagina grazie al servizio fornito dal sito http://validator.w3.org/

W3C validation auto check

Automatically checks the validity of the page with the service provided by the site http://validator.w3.org/

WP-Validate vs W3C validation auto check