Validator.nu Textarea Input
From WHATWG Wiki
To use Validator.nu as a Web service by POSTing a text field, the client issues an HTTP request either to http://validator.nu/ or http://html5.validator.nu/ using the POST method with an multipart/form-data entity body. (application/x-www-form-urlencoded is not supported.) Common parameters are encoded as form fields. The document to check is included as the value of a form field called content. The content field must be the last field in the submission.
The request should set the parser parameter explicitly. Content-Type is synthetized by selecting text/html or application/xml depending on the parser value and clamping the charset MIME type parameter to utf-8).
All field values including the document source must decode as UTF-8.
