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Battery Status API

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.

Note: This API is not available in Web Workers (not exposed via WorkerNavigator).

Interfaces

BatteryManager: Provides information about the system's battery charge level.
navigator.getBattery() Read only: Returns a Promise that resolves with a BatteryManager object.

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((battery) => {
  function updateAllBatteryInfo() {
    updateChargeInfo();
    updateLevelInfo();
    updateChargingInfo();
    updateDischargingInfo();
  }
  updateAllBatteryInfo();

  battery.addEventListener("chargingchange", () => {
    updateChargeInfo();
  });
  function updateChargeInfo() {
    console.log(`Battery charging? ${battery.charging ? "Yes" : "No"}`);
  }

  battery.addEventListener("levelchange", () => {
    updateLevelInfo();
  });
  function updateLevelInfo() {
    console.log(`Battery level: ${battery.level * 100}%`);
  }

  battery.addEventListener("chargingtimechange", () => {
    updateChargingInfo();
  });
  function updateChargingInfo() {
    console.log(`Battery charging time: ${battery.chargingTime} seconds`);
  }

  battery.addEventListener("dischargingtimechange", () => {
    updateDischargingInfo();
  });
  function updateDischargingInfo() {
    console.log(`Battery discharging time: ${battery.dischargingTime} seconds`);
  }
});

Specifications

Specification
Battery Status API # the-batterymanager-interface

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`Battery_Status_API`	38	79	43–52	No	25	No	38	38	43–52	25	No	3.0
`charging`	38	79	43–52	No	25	No	38	38	43–52	25	No	3.0
`chargingTime`	38	79	43–52	No	25	No	42 38–42 Always equal to `0` or `Infinity`.	42 38–42 Always equal to `0` or `Infinity`.	43–52	29 25–29 Always equal to `0` or `Infinity`.	No	4.0 3.0–4.0 Always equal to `0` or `Infinity`.
`chargingchange_event`	38	79	43–52	No	25	No	38	38	43–52	25	No	3.0
`chargingtimechange_event`	38	79	43–52	No	25	No	38	38	43–52	25	No	3.0
`dischargingTime`	38	79	43–52	No	25	No	42 38–42 Always equal to `Infinity`.	42 38–42 Always equal to `Infinity`.	43–52	29 25–29 Always equal to `Infinity`.	No	4.0 3.0–4.0 Always equal to `Infinity`.
`dischargingtimechange_event`	38	79	43–52	No	25	No	38	38	43–52	25	No	3.0
`level`	38	79	43–52	No	25	No	38	38	43–52	25	No	3.0
`levelchange_event`	38	79	43–52	No	25	No	38	38	43–52	25	No	3.0
`secure_context_required`	103	103	No	No	No	No	103	103	No	71	No	20.0

Interfaces

Example

Specifications

Browser compatibility

See also