Secure login for custom authentication

Hi,

Our team is using auth0 for authentication purposes.
We have our own custom UI for login/signup so we are currently using auth0-js library. The problem is using this library exposes raw password over the network when sending an api request, which is an security issue. We understand that there is a custom UI in the universal login, but the logic is complicated that it is nearly impossible to code in bare html.

It would be appreciated if there is any solution to this problem.

Thanks in advance!