It's about installing phonegap native plugin and using it in javascript in Crosswalk.
But you can install phonegap native plugin easily with Intel XDK Tool .
For example:
XDK PORJECTS - your_xdk_project - CORDOVA 3.X HYBRID MOBILE APP SETTINGS - PLUGINS AND PERMISSIONS - Core Cordova Plugins -
set "Events (battery status)" checked state, set version 0.2.7
And like so, you can install any phonegap native plugin like admob and use it with javascript.