How is the contextual advertising system implemented?

Question

JavaScript

Tell me, how are the technical implementations of advertising inserts, in javascript. What's next, on the server side?
That is, for example, Yandex issues a javascript code to be inserted into the site, or some kind of affiliate program. We insert and display any ads, directories. How it works and is called, I can’t even understand what to type in Google. What are these technologies called?

Answer 1

the system such a script makes a request to the server, the server parses the request for parameters, processes it and gives a response. Each of the stages can be implemented by a whole bunch of methods.