Validator.nu Textarea Input
To use Validator.nu as a Web service by POSTing a text field, the client issues an HTTP request either to
http://html5.validator.nu/ using the POST method with an
application/x-www-form-urlencoded entity body. Common parameters are encoded as form fields. The document to check is included as the value of a form field called
content field must be the last field in the submission.
Percent-encoded octets must decode to UTF-8.