ESP32 controller is programmed as a web server communicating with a client web browser using AJAX web technology.

Link to code:
akuzechie.blogspot.com/2020/12/esp32-web-server-us…
Reference:
NodeMCU ESP8266 Communication Methods and Protocols
circuits4you.com/nodemcu-esp8266-communication-met…

Contents:
0:00 Introduction
0:37 AJAX Specs
1:06 ESP32 Client-Server Model
1:50 Block Diagram
2:21 Demonstration
2:46 C++ Sketch
3:20 HTML & CSS Code
5:23 JavaScript Code
7:45 Future Project: ESP32 & WebSocket