It uses either the JS library, jQuery, or the ASP.NET MVC network to act as a layer between applications and DOM access and manipulation code to isolate code from inconsistencies
Enables a page to request or submit data without doing a refresh or postback
Main feature is the XmlHttpRequest object
Uses both synchronous and asynchronous requests to access data behind the scenes (on demand) to greatly enhance the user experience by eliminating the wait for the full page to load