[jQuery] .ajax error function

[jQuery] .ajax error function


My .ajax call is erroring out and I can't figure out why. Was
working fine, and all the sudden quit.
I am looking for an example of the .ajax error function. Documentaion
says: error (Function) - A function to be called if the request fails.
The function gets passed three arguments: The XMLHttpRequest object, a
string describing the type of error that occurred and an optional
exception object, if one occurred.
I tried: error: function(request, settings, expobj). Is that
correct?
expobj=undefined when I display it.
Where can I find a list of errors the .ajax call can return?