Automation of routine tasks in the browser?

Question

macOS

I will forgive the help of those who know how to implement my little idea for automating routine tasks IN THE BROWSER. I would like to explain at least the logic of construction. I work in the Rookee service, I want to write a program that can automatically import csv files. Visually I imagine it like this -> on macOS a program, there is a window in it, and in it a browser, like WEBKit, a couple of buttons -> "upload a folder with files to the database" and a button "start the import process". I thought I could put these files in the database with numbering, and the program will automatically read the name of the file "first file.csv", for example, check it in the browser through the search script, if there is one, it takes the file and imports it according to the script (a couple of actions in the browser perform ), and then deletes the file from the database, and so on with the next one. Well, if there are no such files, it just sends information to the log that was not there and continues to work. I imagined it somehow, so maybe someone knows how to implement it or had experience. I would be grateful if someone can simply explain another version of the implementation in private messages with accessibility. Thanks to those who took the time to read this nonsense)