How to get access token and create twiml request from javascript/browser for Twilio programmable voice?

I am looking for the entire processing of initialisation the call and convert it to conference call on the client side rather than server side. This will improve the performance and eliminate the maitainence work required on the backend side.

I have seen mostly code is in npm. My project doesn't use any front end frameworks. How can I achieve this using pure native javascript/jquery