28674 2015-05-22 02:55:46 +0000 H1-H6 missing from Changed Elements (3.3) 2018-06-02 19:47:10 +0000 1 1 1 Unclassified HTML WG HTML5 differences from HTML4 unspecified All All NEW P2 normal --- 1 duff zcorpan duff mike public-html-admin public-html-wg-issue-tracking uwe.richter.1965 public-html-bugzilla oldest_to_newest 120411 0 duff 2015-05-22 02:55:46 +0000 The definition of the H# elements has changed substantially, but this isn't noted in Section 3.3. 122744 1 zcorpan 2015-08-24 10:49:50 +0000 Can you explain how they changed substantially? 122750 2 duff 2015-08-24 15:48:33 +0000 All in all, the definition has been completely re-written and made more stringent, and includes dependencies on other (new) elements (<section>): - In HTML 4 the definition emphasizes "importance" of the heading. This is (and certainly has historically been interpreted as) orthogonal to the "formal" purpose of headings - specifically - identification of content sections. - In HTML 5 the definition ignores the question of "importance" and restricts ("must") use of H1-H6 to section headings. The heading numbers are "ranks" rather than being indications of importance. - The interaction with <section> is also new to HTML5 - and fundamental to the implementation of H1-H6 (not least, because it allows for more than 6 heading levels). - There are additional specifications for headings in the case of <td> and <blockquote> elements. I hope this helps.