RTCDTMFSender: tonechange event

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("tonechange", (event) => { })

ontonechange = (event) => { }

Event type

An RTCDTMFToneChangeEvent. Inherits from Event.

Event properties

In addition to the properties of Event, this interface offers the following:

RTCDTMFToneChangeEvent.tone Read only

A string specifying the tone which has begun playing, or an empty string ("") if the previous tone has finished playing.

Examples

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>".

This can be done using addEventListener():

dtmfSender.addEventListener("tonechange", (ev) => {
  let tone = ev.tone;
  if (tone === "") {
    tone = "<none>";
  }

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

You can also just set the ontonechange event handler property directly:

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

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

Specifications

Browser compatibility