This provides a base audit of internal libraries (i.e., those not
using a framework like jQuery) to determine the LOE required for
creating a factory to handle CORS or JSON in the browser natively. 

Background:

1.  FF3.5[1]

2.  CORS
https://developer.mozilla.org/En/HTTP_access_control

3.  Navive JSON support
MSIE8, FF3.x, Safari 4, etc. all include native JSON support. 
jQuery 3.3.3
http://dev.jquery.com/ticket/4429



Tests:
1.  Check for eval to loading JSON
return eval('(' + data + ')');
is the canonical form.

2.  Check for XHR through a proxy

Footnotes: 
[1]  https://developer.mozilla.org/en/Firefox_3.5_for_developers