An automatic verification and anti-alteration system for web sites. It distributes the hash value of content and pages among multiple sites, and then checks them for authenticity when the user visits a page. It can be configured to deny access to a corrupted page entirely, or simply remove any javascript if the page appears to be inauthentic, This cooperation should make surreptitious alteration of page data much more difficult and makes delivering an exploit via javascript on a compromised website much more difficult.