RTCDTMFToneChangeEvent.tone

The read-only property RTCDTMFToneChangeEvent.tone returns the DTMF character which has just begun to play, or an empty string (""). if all queued tones have finished playing (that is, RTCDTMFSender.toneBuffer is empty).

Syntax

 var tone = dtmfToneChangeEvent.tone;

Example

This example establishes a handler for the tonechange event which updates an element to display the currently playing tone in its content, or, if all tones have played, the string "<none>".

dtmfSender.ontonechange = function( ev ) {
  let tone = ev.tone;
  if (tone === "") {
    tone = "<none>"
  }

  document.getElementById("playingTone").innerText = tone;
};

Specifications

Browser compatibility

See also

• WebRTC
• Using DTMF with WebRTC
• toneevent
• RTCDTMFToneChangeEvent