How to properly store information in my case?

Question

JavaScript

Hello! Wrote a script to work in Chrome (tampermonkey extension). The script checks if there is new news on the page of the desired site (it is loaded via Ajax), then it immediately informs me about it.
There was a task, to write the numbers of new news in some file, so that later you can always look at it (right now I'm writing this in consol.log()).
Now a couple of questions:
1. For example, in php I understand how to write something to a file, but in js how to write code (and if not saved to a file, then where)?
2. And if our script is in the browser, then how to proceed from there?

Thank you!

Answer 1

IndexedDB
localStorage