API do Estado da Bateria

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This feature is obsolete.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.

A API do Estado da Bateria, mais conhecida como API de Bateria, fornece informação sobre o nível de carga da bateria do sistema e permite-lhe que seja notificado por eventos que são enviados quando o nível da bateria ou o estado de carregamento é alterado. Isto pode ser utilizado para ajustar a utilização de recursos da aplicação para reduzir o consumo de bateria quando a bateria estiver fraca ou para guardar as alterações antes que a bateria acabe para evitar a perda de dados.

The Battery Status API extends window.navigator (en-US) with a navigator.getBattery() (en-US) method returning a battery promise, which is resolved in a BatteryManager (en-US) object providing also some new events you can handle to monitor the battery status.

Exemplo

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.

Especificações

Especificação Estado Comentário
Battery Status API Candidate Recommendation Initial definition

Compatibilidade do navegador

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help! (en-US)

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 39.0 10 (10) moz (en-US)
16 (16)[1]
43 (43)[3]
52 (52)[4]		 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 (en-US)
16.0 (16)[1]
43.0 (43)[3]
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 provides support for the deprecated navigator.battery (en-US).

[2] Values for BatteryManager.chargingTime (en-US) and BatteryManager.dischargingTime (en-US) are always equal to Infinity.

[3] The new promise-based syntax for Navigator.getBattery() (en-US) is supported from Firefox 43 onwards.

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

Consultar também