How to load an external javascript?

Hello everyone,

I want to load a javacript from an external server and I don't understand how to do it. And the owncloud's doc is not clear enough for me : https://doc.owncloud.org/server/9.1/developer_manual/app/js.html

The script is at 'https://domain.com/js/blabla.js' and script('myapp', 'https://mydomain.com/js/blabla.js'); obviously doesn't work.

Could someone help me ?