Note: After saving, you have to bypass your browser's cache to see the changes. Google Chrome, Firefox, Microsoft Edge and Safari: Hold down the ⇧ Shift key and click the Reload toolbar button. For details and instructions about other browsers, see Wikipedia:Bypass your cache.
importScript("User:Csewiki/monobook.js");
importStylesheet('User:Csewiki/monobook.css');
// [[User:Lupin/popups.js]]

mw.loader.load(
             'https://en.wikipedia.org/w/index.php?title=User:Lupin/popups.js'
             + '&action=raw&ctype=text/javascript&dontcountme=s');