title: Is it possible to use external js in a Firefox Extension? e.g. Jquery from CDN
body: <p>I can't find any reference in the docs to using external js in the <a href="https://developer.mozilla.org/en-US/Add-ons" rel="noreferrer">Firefox WebExtensions APIs</a>.  </p>
  
  <p>Most <a href="https://stackoverflow.com/questions/16718347/mozilla-firefox-addons-include-external-library-in-main-js">related Stack Overflow questions</a> are about the old/legacy Add-on SDK. I'm asking about the new WebExtensions APIs</p>
  
  <p>Is it possible?  For example, can I use the <a href="https://code.jquery.com/" rel="noreferrer">Jquery</a> or Bootstrap CDN in my extension? If so, how?</p>