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This feature is obsolete.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.
Specifies an event listener to receive levelchange events. These events occur when the battery level is updated.
Syntax
navigator.battery.onlevelchange = funcRef
Where battery is a BatteryManager object, and funcRef is a function to be called when the levelchange event occurs.
Example
HTML Content
<div id="level">(battery level unknown)</div> <div id="stateBaterry">(charging state unknown)</div>
JavaScript Content
navigator.getBattery().then(function(battery) {
battery.onlevelchange = function(){
document.querySelector('#level').textContent = battery.level;
if(battery.charging)
document.querySelector('#stateBaterry').textContent = "Charging time: " + (battery.chargingTime / 60);
else
document.querySelector('#stateBaterry').textContent = "Discharging time: " + (battery.dischargingTime / 60);
};
});
Specifications
| Specification | Status | Comment |
|---|---|---|
| Battery Status API | Candidate Recommendation | Initial definition |
Browser compatibility
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 38 | ? | 16 — 52 10 — 16 moz 523 | No | 25 | No |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | 40 | 386 | No | 10 — 16 moz 523 | 25 | Yes —? | Yes |
1. 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.
2. From version 52: this feature is behind the dom.battery.enabled preference. To change preferences in Firefox, visit about:config.
3. From this version onwards, the Battery Status API is only available in chrome/privileged code.
4. 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.
5. From version 16 until version 52 (exclusive): this feature is behind the dom.battery.enabled preference. To change preferences in Firefox, visit about:config.
6. Values for BatteryManager.chargingTime and BatteryManager.dischargingTime are always equal to Infinity.