The Twilio.js library allows developers to establish audio connections between a web browser and a Twilio Application. Including the Twilio.js library gives developers access to a couple of objects. One, Twilio.Device, allows one to make outbound connections, accept incoming connections, and set up connection event handlers. Another object, Twilio.Connection, allows an application to interact with a call as it is happening -- mute, unmute, or send DTMF tones. The extensive documentation includes a Quick Start option.