How to create a bot that does automatic actions on the site?

Question

JavaScript

All good. There is an intention to make a bot that will make http requests on a certain site, for example, authorization, downloading the necessary data to my database, in short, everything that can be done manually in a regular browser. (This is feasible, am I not mistaken?) I fully understand that if I am not careful, I can fly into a ban on any site. But the only problem at this point is the lack of any sources of knowledge, I searched like this. I am fluent in C++ with Qt, as well as "web coding" - JS with JQuery, HTML and CSS. There are two ways how I will implement the bot - as a script to the browser (as for me it has a big plus - non-flammability), or in Qt (this is such a shell for creating a GUI interface for the program) via HTTP requests (the method, as I understand it, is hot due to lack of cookies, etc.).
In either of the two cases, I can't figure out how to find the Ajax (most likely it will be used instead of standard PHP tools) script.
Let's say I rummaged through the files dependent on this html page, but I didn’t find exactly what I needed - I can only see how the button is created, I didn’t see more.
I'm confused in short, I only make sites, and do not delve into strangers. Any guidance/advice/tools/anything please.

Answer 1

Separately, look for "web scraper how to" or "Web scraper how to", you can mention the language.
There are a lot of instructions and ready-made projects, and there are a lot of them.
There is a headless chrome.
There is selenium.
Then separately look for information on how to make a bot that accepts commands and sends the result to the messenger. There are also many such tutorials.
And all that remains is to send a request from the bot to the parser, it's simple.

Answer 2

You need to write a browser extension that will execute your JavaScript on other people's sites. The thing you need is called a content script.