The getBattery() method provides information about the system's battery, returns a battery promise, which is resolved in a BatteryManager object providing also some new events you can handle to monitor the battery status.. This implements the Battery Status API; see that documentation for additional details, a guide to using the API, and sample code.


var batteryPromise = navigator.getBattery();

Return value

A Promise which, when resolved, calls its fulfillment handler with a single parameter: a BatteryManager object which you can use to get information about the battery's state.


This example fetches the current charging state of the battery and establishes a handler for the chargingchange event, so that the charging state is recorded whenever it changes.

let batteryIsCharging = false;

navigator.getBattery().then(function(battery) {
  batteryIsCharging = battery.charging;

  battery.addEventListener('chargingchange', function() {
    batteryIsCharging = battery.charging;

For more examples and details, see Battery Status API.


Specification Status Comment
Battery Status API
The definition of 'Navigator.getBattery()' in that specification.
Candidate Recommendation Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 39.0 10 (10) moz
16 (16)[1]
43 (43)[2]
50 (50)[3]
No support 25 No support
Feature Android Android Webview Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support 40.0

10.0 (10) moz
16.0 (16)[1]
43 (43)[2]
50 (50)[3]

No support 25 No support 42.0

[1] Disabled by default in Firefox 10.0, but can be enabled setting the preference dom.battery.enabled to true. Starting with Firefox 11.0, mozBattery is enabled by default. The Battery API is currently supported on Android, Windows, and Linux with UPower installed. Support for the Battery API on Mac OS X is available starting with Gecko 18.0 (Firefox 18.0 / Thunderbird 18.0 / SeaMonkey 2.15). Firefox also provided support for the deprecated navigator.battery until Firefox 50.

[2] The new promise-based syntax for Navigator.getBattery() is supported from Firefox 43 onwards.

[3] The navigator.battery property was removed in Firefox 50.

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API Battery API Device API getBattery Method Navigator Reference