電池事件

// Get the battery API
navigator.getBattery().then(function(battery) {
    battery.addEventListener('chargingchange', function(){
        console.log( 'New charging state: ', battery.charging );
    });

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

    battery.addEventListener('chargingtimechange', function(){
        console.log( 'New time left until full: ', battery.chargingTime, " seconds" );
    });

    battery.addEventListener('dischargingtimechange', function(){
        console.log( 'New time left until empty: ', battery.dischargingTime, " seconds" );
    });
});