Through the study of this course, you can learn about Ajax concepts, HTTP request concepts, PHP simple syntax, JSON data format, Ajax native and jQuery implementation, cross-domain knowledge, etc. It only takes some time, and it may seem like complex knowledge points, but in fact They are all paper tigers and will be broken by you when you poke them. You will not only understand the use of Ajax, but also understand the principles of Ajax and draw inferences from one example.