XHR is a mechanism used to send HTTP/S requests to a web server, and use the response to alter the current document without loading a new page. XHR performance is an important metric for Web site performance monitoring. A significant metric is the client side processing of the response, because of its potential for isolating a pure client side performance problem. The disclosed technique provides a unique way of measuring this metric.
Shershevsky, Olga; Kabizon, Avi; and Pluderman, Nir, "Mechanism For Measuring XHR Client Side Processing", Technical Disclosure Commons, (November 26, 2016)