You will need to use the Navigator.getBattery() method to access the battery information of the device. This method returns a Promise that resolves to a BatteryManager object, which contains information about the battery level, charging status, and other properties.
Here is an example of how you can use the Navigator.getBattery() method to create a real-time battery level indicator:
This code uses the level property of the BatteryManager object to get the current battery level and then sets the width of the progress bar to match.
The addEventListener() method is used to listen for the levelchange event, which is fired whenever the battery level changes, so the progress bar can be updated in real-time.