No.
The HTML version is pure HTML+CSS, not scripted.
The CHM version (I guess that's Windows and Wine only) does have a table
of contents but if it has an index then that's not displayed by Sumatra,
the reader I use for CHM. Unfortunately Microsoft chose to discontinue
support for their various help file formats, in their usual
sabotage-the-user style. Possibly to force users to use their online docs.
Disclaimer: the folder I have this in is dated March 16 2019.
And I haven't really used it. I guess one could use a local fast search
engine. Unfortunately Microsoft sort of discontinued their "index
server" local search, except the part that willy-nilly inspects files so
that USB drives can't be unmounted so that you can't turn off that
laptop, and Google's thing, I think it's also discontinued now, greedily
indexed everything within anything that it could spot, as I recall. Why,
you have secrets from Google? Silly you. Use our search.
- Alf