What is Ajax refreshless technology?

The browser instantiates an Ajax object, which sends an HTTP request and carries certain parameters and transmits it to the background. The background server receives these parameters, filters the passed parameters at the same time, and makes logical judgments. If database operations are required, the data must be retrieved and formatted. Returned to the front-end client, the data obtained by the front-end is processed, the DOM elements are obtained, and the data is placed locally. This enables countless new technologies. It is generally used mainly for registration module email and user verification.