This API is available on Firefox OS for internal applications only.
The muted property of the Telephony interface indicates whether or not the microphone is muted for the purposes of telephony.
Syntax
// Is the phone muted? var muted = myTelephony.muted; // Mutes the phone myTelephony.muted = true;
Value
 A Boolean — true indicates the microphone is muted; false indicates that it is not. You may read and write this value.
Examples
// Telephony object
var tel = navigator.mozTelephony;
// Receive a call
tel.onincoming = function (e) {
  var incomingCall = e.call;
  // Answer the call
  incomingCall.answer();
};
// Say we have a button that mutes/unmutes the phone
muteButton.onclick = function() {
  if(tel.muted) {
    tel.muted = false;
  } else {
    tel.muted = true;
  }
}
Specifications
| Specification | Status | Comment | 
|---|---|---|
| Web Telephony | Draft | Draft | 
Browser compatibility
For obvious reasons, support is primarily expected on mobile browsers.
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari | 
|---|---|---|---|---|---|
| Basic support | No support | No support | No support | No support | No support | 
| Feature | Android | Firefox Mobile (Gecko) | Firefox OS (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | 
|---|---|---|---|---|---|---|
| Basic support | No support | 12.0 (12.0) | 1.0.1 | No support | No support | No support |