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.
battery read-only property
BatteryManager which provides information about the system's
battery charge level and whether the device is charging and exposes events that fire
when these parameters change. This interface was introduced in early drafts of the Battery Status API and but has
been replaced with
var battery = navigator.battery;