This page has the to-do list for the W3C HTML Validation Service, including bugs that need fixing and general wishlist items. See also the www-validator mailing list archives for recent discussion that may not be reflected on this page.

These items are roughly in prioritized order; i.e. the items near the top are those which I consider most important.

1. Finish up the textarea for testing short HTML fragments.
2. Add a "fix my HTML for me" option using Tidy.
3. Finish adding support for XML validation (see also: test cases, or an existing service).
4. Update sgml-lib.tar.gz; automate the updates.
5. Make lists of "most frequently validated invalid pages" and "most frequently validated (non-W3C?) valid pages" (need to start logging stuff first, including IPs to compare uniqueness).
6. Create a stylesheet and link to it from every page.
7. Add a section to the report on document cacheability? (or just link to it?)
8. Put the explanations in a database (flat files are probably okay), and offer an option to display them inline with the errors.
9. Install and play with HTML::Validator, link to it from somewhere: http://www.hut.fi/~samzait/HTML-Validator/ http://www.cpan.org/modules/by-authors/id/S/SA/SAIT/
10. Write documentation, describing each feature and option of the validator and answering questions like "What's the difference between an SGML parser and Weblint?", "Which DOCTYPE should I use?", content negotiation, ...
11. Incorporate CSS validation directly into this service.
12. Make e.g. http://validator.w3.org/check/referer;imgonly return only an image showing the validation status of the referring page.
13. Add link validation using Hugo's checklink code (or other code with similar functionality).
14. Give errors/warnings related to markup that is technically valid SGML, but error prone, such as things found in "B.3 SGML implementation notes" in the HTML 4.0 spec. (these things really belong in something like weblint).
15. Make an "elements found" section a la Webtechs, with links from each element to the appropriate place in either the DTD tree listing produced with dtd2html (after running dtd2html with all DTDs in the catalog), or the HTML 3.2/4.0 specs, or htmlhelp.com stuff, ...
16. Add a "document meta-information" section to the report, to encourage people to use META tags appropriately?
17. Add a "recommend a DTD for me" feature (check a document against all available DTDs, report which one has the fewest errors)
18. Start caching validation results locally and doing an If-Modified-Since HTTP request to only download and re-validate URLs if they actually changed since their last validation
19. Site walker/validator: need to add a "registered user" feature first, because this feature could be abused (many requests on a server in a short period of time)?
20. URL-minder service: "remind me if this page or set of pages ever ceases to validate"
    • "registered user" feature is also necessary for this (to prevent unwanted e-mail)
    • "registered users" could have a list of URLs they're interested in, and whenever they return to the service they can modify this list, and e-mail can be sent whenever any of them cease to validate
    • Right now someone could probably use the existing URL-minder service instead of writing a new one (tell it to "mind" the URL that points to the validation result for a page?) But I'm not sure how regularly URL-minder checks for changes; it seemed to be weekly or something, which isn't frequent enough, IMO. Doing an If-Modified-Since GET every day doesn't cost much if pages don't change. Some of these features should only be enabled if the page consistently returns a Last-Modified header, maybe.
21. Add an HTML pretty-printer feature, using tidy?
22. Provide messages in different languages?
23. Add a graphical representation of the document's structure, using GIFs-mixed-with-text, or an entire GIF?
24. Add a section with PICS info?
25. Issue PICS labels for documents that do/don't conform? Or for editing tools that don't conform?
26. Add support for https:// (TLS/SSL).
27. Figure out what's going on with this. (Thanks to Marie Taylor-Harper for catching this!).
28. Pay attention to Accept-Charset (cf. this message from "brewhaha").
29. Clarify the wording regarding valid characters in errors.html (cf. this message from Clemens Radl. Thanks Clemens!)
30. Fixup all pages to XHTML 1.0 Strict; perhaps take the opportunity to redesign layout and look?
31. Double check that all output is valid! In particular, use style rules to specify heigth/width on suggested links.
32. Write documentation for the SGML catalog, point out good DOCTYPEs to use, and make it easy to find if your editor won't insert them for you.
33. Investigate validation of RDDL.
34. Add catalogue of online tools and other validators. In particular, link to the WDG tools and Nick Kew's most excellent *Valet tools.
35. Add count of errors found in page?
36. Fix directories differing only in name case in sgml-lib/pro/usr/local/lib/sgml/. We have both "ietf" and "IETF" in there.
37. Add system requirements for NT/W2K. Bug Bjoern about his "Installing the Validator on NT" doc. Link to ActiveState Text::Iconv and friends.
38. Add docs on editing DTDs.
39. Link to Jukka's pages; both in general and to specific pages. Ask him about mirroring some of the stuff on validator.w3.org.
40. Do a great big update of the various badges; the details of size, transparency, naming, and how they are linked to (v.w3.org vs. w3.org).
41. Make sure we output sane "text/html; charset=foo".
42. Document how to add new DOCTYPEs to the Validator.