RTCSctpTransport - Web APIs
possibly the most useful property on this interface is its maxmessagesize property, which you can use to determine the upper limit on the size of messages you can send over a data channel on the peer connection.
... rtcsctptransport.maxmessagesizeread only an integer value indicating the maximum size, in bytes, of a message which can be sent using the rtcdatachannel.send() method.

nsIMsgIncomingServer
loginatstartup boolean logonfallback boolean maxmessagesize long offlinesupportlevel long password acstring passwordpromptrequired boolean if the password for the server is available either via authentication in the current session or from password manager stored entries, return false.

RTCPeerConnection.sctp - Web APIs
example var pc = new rtcpeerconnection(); var channel = pc.createdatachannel("mydata"); channel.onopen = function(event) { channel.send('sending a message'); } channel.onmessage = function(event) { console.log(event.data); } // determine the largest message size that can be sent var sctp = pc.sctp; var maxmessagesize = sctp.maxmessagesize; specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'rtcpeerconnection.sctp' in that specification.