If your question is whether HTML5 is backward-compatible with IE6, then the answer is yes (as much as possible). It should be noted that much of the parsing com

If your question is whether HTML5 is backward-compatible with IE6, then the answer is yes (as much as possible). It should be noted that much of the parsing complexity and looser validation are simply observations from IE6's behavior. The new elements and attributes are mostly just ignored in IE6 (article, input type=url, etc.) As for unclosed tags and unquoted attributes, they have been around since HTML 1.0[1], so I don't think you can blame HTML5 for introducing them. [1]: http://www.w3.org/History/19921103-hypertext/hypertext/WWW/MarkUp/Tags.html http://www.w3.org/History/19921103-hypertext/hypertext/WWW/M...