How to create a browser bot plugin?

Question

Browsers

Hello!
There was a task to write an extension for a browser that would switch between tabs, fill out forms with pre-prepared text, send them, click on buttons, etc.
And so that he performs all these actions in a cycle.
An important point is that in some fields there will be counters
.
I myself know html, css, js, php
In general, the standard set of a web developer
A question for connoisseurs, under which browser to write an extension (another important point, I have a mac, so ie doesn’t channel), in what language it should happen and if it’s not difficult , then throw off links to training materials "for dummies" :)

Answer 1

https://developer.chrome.com/extensions/getstarted here provides the necessary information for writing an extension and working with the chrome API.