Obsolete since Gecko 50 (Firefox 50 / Thunderbird 50 / SeaMonkey 2.47)
This feature is obsolete.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 read-only property returns a BatteryManager provides information about the system's battery charge level; provides 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.
The battery property has been removed in favor of the standard Navigator.getBattery() method, which returns a battery Promise. Its support is still partial though.
Syntax
var battery = navigator.battery;
Specifications
| Specification | Status | Comment | 
|---|---|---|
| Battery Status API The definition of 'Navigator.battery' in that specification. | Candidate Recommendation | Initial definition | 
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari | 
|---|---|---|---|---|---|
| Basic support | 38.0 | 10 (10) moz[1] 16 (16)[2] 50 (50)[3] | No support | No support | No support | 
| Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | 
|---|---|---|---|---|---|---|
| Basic support | ? | 38.0 | 10.0 (10) moz[1] 16.0 (16)[2] 50.0 (50)[3] | No support | No support | No support | 
[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.
[2] 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).
[3] Removed in Firefox 50, in favor of navigator.getBattery().