This parser modify the code from HTML5 outliner from Google Code to add a method that insert a value for the attribute "aria-level". This value is calculated from the tree of the outliner.
You can obtaine the same result of the HTML5 outliner if you use the HeadingsMap addon for Firefox.
For more information about the HTML5 algorithm please visit, Sections and Outlines of an HTML5 Document .
There are several HTML tests pages with differents examples of sections, nav, headings, etc... Each test contains the HTML and the result output by the HTML5 outliner.
Refactor the code of the HTML5 outliner.
Please, feel free to report any issue you experiment via Github.