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/DOM

BatteryManager.level

Indicates the current battery charge level as a value between 0.0 and 1.0.

Syntax

var level = battery.level

On return, level is a number representing the system's battery charge level scaled to a value between 0.0 and 1.0. A value of 0 means the battery, which is a BatteryManager object, is empty and the system is about to be suspended. A value of 1.0 means the battery is full. A value of 1.0 is also returned if the implementation isn't able to determine the battery charge level or if the system is not battery-powered.

Example

HTML Content

<div id="level">(battery level unknown)</div>

JavaScript Content

navigator.getBattery().then(function(battery) {
       
    var level = battery.level;

    document.querySelector('#level').textContent = level;
});

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.