Browser implementation is broken

[janpio]

The browser implementation of this plugin uses navigator.getBattery:

https://developer.mozilla.org/en-US/docs/Web/API/Navigator/getBattery

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This feature is obsolete.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.

Current Firefox and Edge don't support it, Chrome still seems to:
https://developer.mozilla.org/en-US/docs/Web/API/Battery_Status_API#Browser_compatibility

As far as I know there is no proper replacement.