Wed. 31st August, 2011
One of the goals of this project is to have proper W3C validated output in the frontend of TYPO3, mostly produced with css_styled_content and cms. TYPO3 claims it can output with various doctypes, including HTML4, several XHTML variants and HTML5. But is that claim correct? Not really. TYPO3 output is a mixture of XHTML, like closing void tags with a slash (<br />) and HTML, for instance targets, sometimes hardcoded in the source code. Furthermore, while you can change the doctype to HTML5, you won't find any HTML5 tags in the core. Up until now it seems that TYPO3's handling of doctypes has been, at best, only partially implemented.
This is a companion discussion topic for the original entry at https://typo3.org/article/html5-and-accessibility-in-typo3-laying-a-foundation-for-the-future/