What is the difference between ar-frame and a-frame?

A a-frame was developed by XXXX (html here) in order to make it easier from developers to deploy 3D graphics in their web pages. It runs in any browser, and while it can be used to create VR experiences, it is not by itself capable of fashioning AR. ar-frame builds on a-frame and allows the developer to create AR (as well as VR) experiences that run in the Argon Web Browser. ar-frame was designed and implemented by Prof. Blair MacIntyre of the Augmented Environments lab at Georgia Tech.