Per the help center on topic page:
and it is not about …
- websites or web services like Facebook, Twitter, and WordPress,
Another line for other off topic items includes the clarification
... except insofar as they interface with your computer,
Your question is not about how it interacts with your browser, it is about how the website works itself and as such is off topic. It has nothing to do with your computer hardware or software.
There is Web Applications but your problem isn't really about using a web application either, it is about the internals of a website, how it works and what it does.
The problem is that any given site can work in any way from outright copying websites to simply buffering requests and any combination in-between and it is impossible to say, broadly speaking, that they all do one or another method or haven't come up with a new way of working. The only people who know how their site works is the people who made it.
There isn't always a Stack Exchange site where a question fits. Sometimes it just doesn't fit any sites on the network at all and we have never claimed to be able to have sites for every single field of human expertise.