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/DOM

BatteryManager.onlevelchange

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	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	39.0	10 (10) moz 16 (16)^[1] 52 (52)^[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] 52.0 (52)^[3]	No support	25^[2]	No support	42.0^[2]

[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 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.

[2] Values for BatteryManager.chargingTime and BatteryManager.dischargingTime are always equal to Infinity.

[3] From Firefox 52 onwards, the Battery Status API is only available in chrome/privileged code.