scripting for preprocessing, also embedded scripts for live ebooks

[hgkamath]

Is your feature request related to a problem? Please describe.
na, this just an inquiry, to check if possible, or even if this a direction that vivliostyle has considered.

Describe the solution you'd like
Investigating possibility of
a) programmatically through hooks, if by acting on the input-src-file, gather additional static content on local system (or by url), pre-process content for inclusion before the usual markup driven typesetting
b) embedding code(JavaScript) and data (json) into a epub/pdf to create say a live ebooks with interactive canvas (such as data visualization, running simulations with parameters, etc).

Being a javascript project, it is to be expected that if there is a scripting language it is JavaScript/wasm.

Describe alternatives you've considered
na, this isn't something traditional typesetters can do.

Additional context
na

If possible, please do include a write-up/documentation somewhere as to how something like this can be done.

Feel free to close the issue if not relevant.

[MurakamiShinyu]

There have been feature requests such as:

• Allow JavaScript in HTML documents #733

and we implemented this feature in:

• Allow JavaScript in HTML documents #824

However, this implementation has limitations and may not be useful for your purpose. See issue:

• Styles not applied to elements created with javascript #975

Also embedded scripts for live ebooks are not possible for now.

We welcome your contribution!