[O] embed an iframe behind a presentation?

[Matt Price]

Hi everyone,

I don't think this is really an org question, but, well, here I am and
I hope someone can help.

I use org-html5presentation.el (this one, I'm pretty sure:
https://github.com/twada/org-html5presentation.el) to generate html5
presentations from org outlines; I do this for my lecture notes, and
the exported files look like this:

http://www.mercey.org/03-public-sphere.html

I thought it might be fun to embed a twitter feed in the slide
background, so students can ask questions or have conversations about
what we're doing while I talk. I had thought I'd just insert an iframe
containing a twitter widget into the background somewhere.
Unfortunately, I actually don't understand how these presentations are
really produced, or how I would insert code into the background.  Most
of the formatting seems to be done in css, and the dynamic movements
of the slides is triggered I guess somehow by javascript; but this is
all html5 black magic to me.  I'm not sure how I would, effectively,
change the 'template' for the presentation to one that includes the
appropriate iframe.

Like I say, I'm not entirely sure this is an org question, but I'd
still love some guidance if folks cna provide it.  Thanks as always,
Matt