Use validate local html in the web developer toolbar (firefox). There are others in in other browsers I am sure.
You cannot validate your whole site to my (limited) knowledge
Dave
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From: support-bounces@drupal.org [mailto:support-bounces@drupal.org] On Behalf Of Anthony Sent: Friday, June 29, 2012 9:22 AM To: support@drupal.org Subject: [support] W3C validation
I would like to validate my drupal sites. How ? Thanks