Validator.nu POST Body Input
To use Validator.nu as a Web service by POSTing an entity body, the client issues an HTTP request either to
https://html5.validator.nu/ using the POST method. The document to check is included as the entity body of the request. The
Content-Type request header must be used to communicate the MIME type of the entity body. Common parameters are encoded as query string parameters.
& is supported as a query parameter separator.
; is not supported.
Percent-encoded octets in the query string must decode to UTF-8.