示例
//获取电池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" );
});
});
