Markup Validation Service

Notes and Potential Issues

The following notes and warnings highlight missing or conflicting information which caused the validator to perform some guesswork prior to validation, or other things affecting the output below. If the guess or fallback is incorrect, it could make validation results entirely incoherent. It is highly recommended to check these potential issues, and, if necessary, fix them and re-validate the document.

1. No Character Encoding Found! Falling back to UTF-8.

   None of the standards sources gave any information on the character encoding labeling for this document. Without encoding information it is impossible to reliably validate the document. As a fallback solution, the "UTF-8" encoding was used to read the content and attempt to perform the validation, but this is likely to fail for all non-trivial documents.

   The sources used to find encoding information include:

   • The HTTP Content-Type header.
   • The XML Declaration.
   • The HTML "META" element.

   The algorithm defined in Appendix F of the XML 1.0 Recommendation was also used, without success.

   Since none of these sources yielded any usable information, reliable validation of this document is not possible. Sorry. Please make sure you specify the character encoding in use.

   Specifying a character encoding is typically done by the web server configuration, by the scripts that put together pages, or inside the document itself. IANA maintains the list of official names for character encodings (called charsets in this context). You can choose from a number of encodings, though we recommend UTF-8 as particularly useful.

   The W3C I18N Activity has collected a few tips on how to declare the encoding of a Web document.

   To quickly check whether the document would validate after addressing the missing character encoding information, you can use the "Encoding" form control earlier in the page to force an encoding override to take effect. "iso-8859-1" (Western Europe and North America) and "utf-8" (Universal, but not commonly used in legacy documents) are common encodings if you are not sure what encoding to choose.

2. DOCTYPE Override in effect!

   The DOCTYPE Declaration for "HTML 4.01 Transitional" has been inserted at the start of the document, but even if no errors are shown below the document will not be Valid until you add the new DOCTYPE Declaration.

3. No Character encoding declared at document level

   No character encoding information was found within the document, either in an HTML meta element or an XML declaration. It is often recommended to declare the character encoding in the document itself, especially if there is a chance that the document will be read from or saved to disk, CD, etc.

   See this tutorial on character encoding for techniques and explanations.

Congratulations

The document located at <https://digitalmars.com/d/index.html> was tentatively checked as HTML 4.01 Transitional. This means that with the use of some fallback or override mechanism, we successfully performed a formal validation of it. In other words, the document would validate as HTML 4.01 Transitional if you changed the markup to match the changes we have performed automatically, but it will not be valid until you make these changes. The parser implementations we used for this check are based on OpenSP (SGML/XML).

Linking to this result

If you would like to create a link to this page (i.e., this validation result) to make it easier to revalidate this page in the future or to allow others to validate your page, the URI is <https://validator.w3.org/markup/check?uri=https%3A%2F%2Fdigitalmars.com%2Fd%2Findex.html;verbose=1> (or you can just add the current page to your bookmarks or hotlist).

Validating CSS Style Sheets

If you use CSS in your document, you can check it using the W3C CSS Validation Service.

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