RTCDataChannel.id

The read-only RTCDataChannel property id returns an ID number (between 0 and 65,534) which uniquely identifies the RTCDataChannel. This ID is set at the time the data channel is created, either by the user agent (if RTCDataChannel.negotiated is false) or by the site or app script (if negotiated is true).

Each RTCPeerConnection can therefore have up to a theoretical maximum of 65,534 data channels on it, although the actual maximum may vary from browser to browser.

Syntax

var id = aDataChannel.id;

Value

An unsigned short value (that is, an integer between 0 and 65,535) which uniquely identifies the data channel.

While the label property doesn't have to be unique, this ID number is guaranteed to be unique among all data channels. Additionally, known implementations of WebRTC use the same ID on both peers. A unique ID makes it easier for your code to do its own out-of-band data channel-related signaling.

This can be also useful for logging and debugging purposes.

Example

var pc = new RTCPeerConnection();
var dc = pc.createDataChannel("my channel");

console.log("Channel id: " + dc.id);

Specifications

Browser compatibility

[1] The interface is called DataChannel and not RTCDataChannel in Firefox, although a binding was added in Firefox 24 which allows either name to be used.

[2] Available in Firefox 22 as RTCDataChannel.stream, however.

See also

• WebRTC
• RTCDataChannel
• RTCPeerConnection.createDataChannel()