Protesilaos Stavrou <info@protesilaos.com> writes:

> With regard to the disambiguation scheme, I am playing around with
> various scenaria to see how Org HTML export behaves. Using the
> following:
> ...
>     This is test 2 <sup><a id="fnr.1.100" class="footref" href="#fn.1" role="doc-backlink">1</a></sup>
> ...
>     This is test 3 <sup><a id="fnr.1.100" class="footref" href="#fn.1" role="doc-backlink">1</a></sup>
>
> Notice that the 100 in the ID is not incremented further. I guess this
> is something that can be worked on but, again, I think it is separate
> from the issue of using the label for the ID and HREF.
>
> Any thoughts?

Duplicate IDs are against HTML spec:
https://softwareengineering.stackexchange.com/questions/127178/two-html-elements-with-same-id-attribute-how-bad-is-it-really

So, this is a bug.

>>> Though I should have clarified my intent earlier: the idea is to use the
>>> label as a fixed reference to the footnote, so that the link does not
>>> change between exports. This is the same principle as what we do with
>>> links to headings that have a CUSTOM_ID.
>>>
>>> As such, the anchor text can still be the way it is now as an
>>> automatically generated number sequence (^1, ^2, etc.), but the HTML
>>> "id" and "href" values will be constructed based on the label of the
>>> footnote, NOT its number in the sequence.

See the attached tentative patch.