Plone 5 external resources

Is it possible to register an external javascript with Plone 5?

In my use case I need to add this resource: // and get this error:

2018-04-20 09:08:49 ERROR plone.subrequest Error handling subrequest to http://localhost:8080/Plone2///

And the expected was to point to the external content instead (adding just the current http or https) into the resource url.

The same should happen if for example I need to add a resource from a CDN.

plone.subrequest is for performing requests inside the Zope 2 tree only.
Either register your Javascript with the resource registry or include the JS directly from the template(e) that require this particular JS module.

Let's move the discussion into this bug report: