A worker is an object created using a constructor (e.g. Worker()) that runs a named JavaScript file — this file contains the code that will run in the worker thread; workers run in another global context that is different from the current window. Thus, using the window shortcut to get the current global scope (instead of self) within a Worker will return an error.
The Alarm API allows applications to schedule actions to be run in the future. For example, some applications like alarm-clock, calendar or auto-update might need to utilize the Alarm API to trigger particular device behaviors at specified time points.
This method is used to access to one of the cameras available on the device based on its identifier. You can get a list of the available cameras by calling the CameraManager.getListOfCameras() method.