title: Run a JS Userscript through Tampermonkey on a Chrome Extension
body: <p>I have a working JS Userscript intended for running an action when clicking on any word in a webpage.  This works fine when installed either with Greasemonkey in Firefox or Tampermonkey in Chrome on all webpages.</p>
  
  <p>However, I would like for the script to be able to be run (or perhaps have access to run) on a Chrome Extension, specifically the open-source EPUB reader Readium.  This is a type of Chrome extension that installs with an icon, and opens up a new tab with a URL starting with "chrome-extension://...".</p>
  
  <p>Userscripts have the ability to include and exclude websites with a set of tags at the top of the page, and I've attempted to include all websites, all sites beginning with :chrome-extension", all anything, etc., and not only is the code not working, Tampermonkey is not showing that the script is running and the console is not logging any test examples.</p>
  
  <p>So my question is, is there any way to run Chrome Extension/app A, downloaded from the Chrome store, and have Userscript B, running through Tampermonkey, inject JS code into the chrome extension A?</p>