Validator.nu Useful Warning Requests

This page documents requests for potential optional checks to be implemented by HTML5 QA tools, like Validator.nu. This is only intended to document feature requests, and may not reflect what is, or will be, implemented in the future.

The following tables describe issues that a QA tool might provide options to warn about. None of the issues listed in these tables are technically conformance errors, but have been requested directly by authors and/or are considered to be useful for authors to be warned about.

Syntactic Issues

Title	Description	Notes
Quoted attributes	Boolean option to require quoted attribute values for all attributes.	XHTML-like syntactic convention commonly requested by authors. (request)
Minimised attributes	Boolean option to require all boolean attributes to use the non minimised form. e.g. <input disabled="disabled"> instead of <input disabled>	XHTML-like syntactic convention commonly requested by authors.
Trailing Slashes	Options to either: Warn about unnecessary trailing slashes in void elements Require trailing slashes for in void elements None (default)	Some authors like to follow the XML convention, others prefer to always omit them, and others don't care that much. (request)
Optional </p> ahead of new structural element	Boolean option to warn about omitted paragraph end tags ahead of start tags of section, nav, article, aside, header and footer
Optional End Tags	Boolean option to require end tags for all non-void elements, which normally have optional end tags	(request)
Optional Start Tags	Options to require start tags for the elements 'html', 'head', 'body' and 'tbody'.	XHTML-like convention, mostly applies to html, head and body. Some authors still choose to omit tbody, but like to always include the others.
Named Entities	Options to allow: The 5 predefined named entity references only (lt, gt, amp, quot, apos) HTML 4.01 entity references only XHTML 1.0 entity references only (request) All named entity references	Warning about HTML4.01 references is a useful check for compatibility reasons, due to existing legacy browsers that don't support the additional entity references imported from MathML yet. Use of only the 5 predefined entity references is needed for those who want XHTML compatibility, without a DOCTYPE.

Other Warnings

Title	Description	Notes
Untitled document	Warn about the use of meaningless or empty titles. e.g. <title>Untitled document<title> (or similar)	This is a common default title inserted by authoring tools. Advise the author to use a more appropriate title for the document. (request)
Unnecessary whitespace	Warn about long stretches of unnecessary whitespace	(request)