Fight Club Starter Kit

Code interacting with browser extensions can live in four places:

0. Background scripts
1. Content scripts
2. Injected scripts
3. Your web app

This Stack Overflow answer has a great shorthand explanation for each. It also might help to start by taking a look at the minimum viable Chrome Extension.

This repo demonstrates how to use a content script to enable your web app to talk to the extension's background script, which has full access to the chrome.* APIs.

Next-level $#!t

Learn how to create a build process and the basics of mapping Chrome resources to Safari and Firefox in Developing Cross Browser Extensions by @alexbeletsky.