Umlaut base URL
The first argument is your Umlaut base URL. This is not your link resolver base url which for Umlaut ends in /resolve, but the actual Umlaut application base URL, which should be the same, without the /resolve. (Link to JHU example removed, because i think it was attracting malicious bot/spider traffic)
The second argument is a URL-formatted (KEV) OpenURL context object.
The fourth argument is a hash of additional options to embedUmlaut.
The html loaded will sometimes include a "spinner" with a message "loading more", if the content is not yet loaded.
An example is best: