The WebRTC specification has defined an API for the SCTP transport:

http://w3c.github.io/webrtc-pc/#rtcsctptransport-interface

This should be exposed at the javascript layer.
Some aspects seem to be visible in WebRTC through the PC API, but perhaps not all.

WPT test:

https://wpt.fyi/webrtc/RTCSctpTransport-constructor.html

https://wpt.fyi/webrtc/RTCSctpTransport-maxMessageSize.html