Because XMLhttpRequests ("Ajax") have serious problems with older browsers
and does not work with all charsets in all browsers
CBA uses another (in my opinion better) solution by appending a javascript into your bodycontent.
By CBA instead we get a truly great functionality being able to work with Ajax functionality.
jQuery have awesome features with .loading, $.get and $.ajax
however all of these are using XMLhttpRequests, which does not work in old browsers
in explorer it uses an activeX component, which (as we all know) is far from awesome
in Gecko/webkit based browsers you can use an override for the charset problems
but it does not work in IE (not even latest versions)
What depencies does this script collection have?
*jQuery
*cba (make sure you get the patched version i uploaded in the bug's section on sourceforge, or it will fail in FF > 4.)