Thank you so much Lithopsian. It looks like from [1] that I can use pure JS for this plugin, since the tabs api [2] is a top-level api, right? Later on, I am not sure if the new Chrome-like way [3] will deprecate the JS code? Or will JS still be supported?
Anne
1.[]Main page has debugging , etiequette, performance etc info on how to do a plugin ; ; ; X.Add-ons - Mozilla | MDN ;; https://developer.mozilla.org/en-US/Add-ons
2.[]JavaScript Examples and details about specifially the tab api ; ; This is in the top-level api, so XUL is not required. ; ; X.tabs - Mozilla | MDN ;; https://developer.mozilla.org/en-US/Add-ons/SDK/High-Level_APIs/tabs
3.[] NEW way ; ; ;similar? notify-link-clicks ; it has an injected code into all pages, and the background-script.js that listens to all the pages ; ; X.Example WebExtensions - Mozilla | MDN ;; https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Examples