Validates the current site (using the online W3C Validator) in the background, checks the result and shows then some HTML (”valid” Icon, Text or whatever) for both possible results (valid, invalid). This make’s it possible only to show a “valid” Icon / Text if the current page actually still IS valid. This can be useful for a webmasters to quickly check which pages contain errors, or for those who absolutely want to show such a “valid” Icon / Text on their page. No more worry about if it’s still valid - if not, no Icon will show up.
