title: Cordova Android: how to listenen to custom events in Javascript?
body: <p>with Cordova Android, how can javascript listen to custom event fired in Java code? </p>
  
  <p>A typical use case is when an activity starts, it connects to a back end server and waits until the server sends back a message, then notifies javascript to make UI updates. How should it be done in Cordova?</p>
  
  <p>Thanks</p>