Web/API/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 = "&lt;none&gt;"
  }

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

Specifications

Specification	Status	Comment
WebRTC 1.0: Real-time Communication Between BrowsersThe definition of 'RTCDTMFToneChangeEvent.tone' in that specification.	Candidate Recommendation	Initial specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`tone`	Chrome Full support 27	Edge Full support 12	Firefox Full support 52	IE No support No	Opera Full support Yes	Safari ?	WebView Android Full support 4.4	Chrome Android Full support 27	Firefox Android Full support 52	Opera Android Full support Yes	Safari iOS ?	Samsung Internet Android Full support 1.5

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown