If you host a widget externally rather than pasting its HTML into the External Widget, then - except for the special case of
Scripts and UDIXes are web workers, and therefore they can use importScripts() to load external code. For example, you can host the Javascript for a script externally, and then run it within MyTrader using a single line of code:
importScripts("https://www.myserver.com/myscript.js");
However, such code must both be hosted at an https:// address and also have CORS headers on its response.