The Web Design Group

Validator Tips

Other languages: français

Validating the Referring URL

Validation of the referring URL allows authors to conveniently use the same HTML as a validation link on any page:


To include the document's source, use the following:


One may also use "referrer" in place of "referer".

Validating Password-Protected Documents

To validate password-protected documents, use a URL of the form "". (While this is not a technically valid URL, it is accepted by the WDG HTML Validator for convenience.)

Validating by FTP

The validation by URL form supports HTTP, HTTPS, and FTP. For anonymous FTP, use a URL of the form "". If you need a user name and password, use a URL of the form "".

Using a Custom XHTML or XML DTD

By default, the Validator assumes that a custom DTD is HTML or SGML. If your custom DTD is XHTML or XML, then you need to include the Validator's hidden "xml" option. When validating a URL, you can specify this option by appending "&xml=yes" to the URL of the validation results.

With other validation methods, you need to use your own local validation form that includes the "xml" option (typically using <input type="checkbox" name="xml" value="yes">).

Robot exclusion when validating an entire site

When the "Validate entire site" option is selected, the Validator will abide by the Robots Exclusion Protocol, allowing you to block the Validator from spidering certain sections of your site. To specify rules specifically for the Validator in your robots.txt file, use "WDG_SiteValidator" as the User-agent.