Loading screen help (newbie somewhat)

So, I’m working on this Rails site, mostly doing Javascript bug

The site’s a bit of a mess.

Anyhow, the guy who owns the site wants a loading screen put in for
the main page. The main page renders a whole bunch of widgets and
relies heavily on some dhtmlgoodies scripts…

I already know how to throw in a loading screen, the issue I’m having
is how to integrate it with the rest of the Rails site in such a way
that the contents of it are customizable by the admin. I figure that
the easiest way to make it customizable will be to make a model, view,
and controller for it and do the appropriate checks…

This is mostly an issue of me being new to rails.

I guess the flow should look something like this:

User logs in:
Loading screen displayed
Rest of page renders in background
Loading screen hidden

Does rails have a easy way to accomplish this?

Like I said, I can accomplish this outside of the context of rails,
but that would make it quite annoying to add in the ability for the
admin to modify it. . . and would break the continuity of the site,
make it annoying for any developers coming in after me, etc.

Any points in the appropriate direction would be appreciated -
relevant sections of the Rails API, etc.