[keycloak-user] Get token for JS UI

I have a situation where I need my javascript UI (all client side) to obtain a token from Keycloak. The token would not be specific to the user but for the UI itself. Looking at the documentation for the Javascript Adapter, it appears that it only works for getting a token for the user and is a public access type. Is it possible to get a token for the UI and treat the UI as a confidential client? It would need to then have a secret key, right? Is there a good way to store that secret key so that it can't be read by users who just browse the source from their browser? The reason for doing this is I have another authentication engine that is used to access the UI. The users would then not have an account in Keycloak.