Battery Status API

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

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

  battery.addEventListener('chargingchange', function(){
    updateChargeInfo();
  });
  function updateChargeInfo(){
    console.log("Battery charging? "
                + (battery.charging ? "Yes" : "No"));
  }

  battery.addEventListener('levelchange', function(){
    updateLevelInfo();
  });
  function updateLevelInfo(){
    console.log("Battery level: "
                + battery.level * 100 + "%");
  }

  battery.addEventListener('chargingtimechange', function(){
    updateChargingInfo();
  });
  function updateChargingInfo(){
    console.log("Battery charging time: "
                 + battery.chargingTime + " seconds");
  }

  battery.addEventListener('dischargingtimechange', function(){
    updateDischargingInfo();
  });
  function updateDischargingInfo(){
    console.log("Battery discharging time: "
                 + battery.dischargingTime + " seconds");
  }

});

See also the example in the specification.

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.
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.
level
38
79
43-52
No
25
No
38
38
43-52
25
No
3.0
onchargingchange
38
79
43-52
No
25
No
38
38
43-52
25
No
3.0
onchargingtimechange
38
79
43-52
No
25
No
38
38
43-52
25
No
3.0
ondischargingtimechange
38
79
43-52
No
25
No
38
38
43-52
25
No
3.0
onlevelchange
38
79
43-52
No
25
No
38
38
43-52
25
No
3.0

See also

© 2005–2021 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/Battery_Status_API