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This API is available on Firefox OS for internal applications only.

The dialEmergency() method of the Telephony interface dials an emergency phone number and returns a new TelephonyCall object representing the new call.


The new syntax is promise-based, and resolves with the TelephonyCall object for the new call:

myTelephony.dialEmergency(number,serviceId).then(function(myTelephonyCall) {
  // do something with the new call

The original syntax (Firefox 1.3 and below) was just a regular non-promise method.

var myTelephonyCall = myTelephony.dialEmergency(number,serviceId);


A string indicating the emergency number to dial.
serviceId Optional
The id of the mobile service you want to use to make the call. If not specified, the default value for the device is used.


A promise that resolves with a TelephonyCall object.


// Telephony object
var tel = navigator.mozTelephony;

// Place a call
tel.dialEmergency("911").then(function(call) {;


Specification Status Comment
Web Telephony Draft Draft

Browser compatibility

For obvious reasons, support is primarily expected on mobile browsers.

Supported in Firefox OS 1.0.1.

Promise version support in Firefox OS 1.4.

See also