Obsolete
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

The Battery Status API, more often referred to as the Battery API, provides information about the system's battery charge level and lets you be notified by events that are sent when the battery level or charging status change. This can be used to adjust your app's resource usage to reduce battery drain when the battery is low, or to save changes before the battery runs out in order to prevent data loss.

The Battery Status API extends window.navigator with a navigator.getBattery() method returning a battery promise, which is resolved in a BatteryManager object providing also some new events you can handle to monitor the battery status.

Example

In this example, we watch for changes both to the charging status (whether or not we're plugged in and charging) and for changes to the battery level and timing. This is done by listening for the chargingchange, levelchange, chargingtimechange, dischargingtimechange events.

navigator.getBattery().then(function(battery) {
  function updateAllBatteryInfo(){
    updateChargeInfo();
    updateLevelInfo();
    updateChargingInfo();
    updateDischargingInfo();
  }
  updateAllBatteryInfo();

  battery.addEventListener('chargingchange', function(){
    updateChargeInfo();
  });
  function updateChargeInfo(){
    console.log("Battery charging? "
                + (battery.charging ? "Yes" : "No"));
  }

  battery.addEventListener('levelchange', function(){
    updateLevelInfo();
  });
  function updateLevelInfo(){
    console.log("Battery level: "
                + battery.level * 100 + "%");
  }

  battery.addEventListener('chargingtimechange', function(){
    updateChargingInfo();
  });
  function updateChargingInfo(){
    console.log("Battery charging time: "
                 + battery.chargingTime + " seconds");
  }

  battery.addEventListener('dischargingtimechange', function(){
    updateDischargingInfo();
  });
  function updateDischargingInfo(){
    console.log("Battery discharging time: "
                 + battery.dischargingTime + " seconds");
  }

});

See also the example in the specification.

Specifications

Specification Status Comment
Battery Status API Candidate Recommendation Initial definition

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Deprecated
Chrome Full support 38Edge ? Firefox No support 16 — 52
No support 16 — 52
No support 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
Full support 52
Notes Disabled
Notes Disabled by default in Firefox 10, but can be enabled setting the preference dom.battery.enabled to true. Starting with Firefox 11, mozBattery is enabled by default. The Battery API is currently supported on Android, Windows, and Linux with UPower installed. Support for MacOS is available starting with Firefox 18. Firefox also provide support for the deprecated navigator.battery.
Disabled From version 52: this feature is behind the dom.battery.enabled preference. To change preferences in Firefox, visit about:config.
Full support 52
Notes
Notes From this version onwards, the Battery Status API is only available in chrome/privileged code.
IE No support NoOpera Full support 25Safari No support NoWebView Android Full support 40Chrome Android Full support 38
Notes
Full support 38
Notes
Notes Values for BatteryManager.chargingTime and BatteryManager.dischargingTime are always equal to Infinity.
Edge Mobile No support NoFirefox Android No support 10 — 16
Prefixed
No support 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
No support 16 — 52
Notes Disabled
Notes 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 MacOS is available starting with Gecko 18.0 (Firefox 18.0 / Thunderbird 18.0 / SeaMonkey 2.15). Firefox also provide support for the deprecated navigator.battery.
Disabled From version 16 until version 52 (exclusive): this feature is behind the dom.battery.enabled preference. To change preferences in Firefox, visit about:config.
Full support 52
Notes
Notes From this version onwards, the Battery Status API is only available in chrome/privileged code.
Opera Android Full support 25Safari iOS No support ? — ?Samsung Internet Android Full support Yes

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Deprecated. Not for use in new websites.
Deprecated. Not for use in new websites.
See implementation notes.
See implementation notes.
User must explicitly enable this feature.
User must explicitly enable this feature.
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also

Document Tags and Contributors

Last updated by: fscholz,