Novice question about debugging deferreds

[Robert Goldman]

I'm a pretty novice Javascript programmer, using MochiKit for an AJAX-
based client. I have been having a lot of trouble debugging (I use
Firebug) and I think I am starting to understand why. As far as I can
tell, there's a try...catch wrapped around the firing of my Deferred
callbacks. Unfortunately, this means that when I get something like a
type error in there, it seems to just vanish, and all I see is my
application fail to respond. Firebug never shows me my error.

This leaves me with a couple of questions:

1. Is this a correct understanding of what goes on?

2. Is there some switch I should use to avoid this behavior? Or is
there some common practice people use to avoid missing important error
information when debugging these callbacks?

The application is a pretty trivial one, displaying output from a
complex program running on the server, so it's particularly prone to
this problem --- almost all the code lies in the callbacks, pulling
stuff out of AJAX messages, processing it, and using it to update the
display.

Many thanks,
r