Originally published February 2020, updated today.
It’s actually been longer (I remember being introduced to the outline algorithm in 2007), but 11 years is a number worth signifying.
In 2020 2021 as it was in 2010 the HTML specification defines an outline algorithm and specifies how it affects heading rank regardless of the hard coded heading level h1…h6 and how automagically transforms multiple headings into a single heading.
Problem is that its never been implemented, as a consequence developers taking the specification as the truth, have been and continue to be misled. The reality of this fantasy has been burned into many [...]