AJAJ is a method which dictates how a client and server interact. Unlike its predecessor AJAX which uses XML, in AJAJ the content sent back and forth between the client and server is strictly JSON.
AJAJ has many advantages over its predecessor AJAX like being lightweight and sending data back and forth in JSON which being JavaScript is faster for the browser to process and easier for developers to work with.
The term AJAJ (an acronym for Asynchronous JavaScript and JSON) has been use since at least 2006.