Found a workaround now to control the user preferences. Its solved now. Here s the Workaround: 1) Passback the 'Device Token' and a boolean flag which indicates whether user allowed push notification or not to the javascript. 2) Pass the values received to the load URL as URL parameters. 3) Using PHP GET will receive these parameters at the server side and store it to a database table.
Now you can devise your own logic in the app to control push notification to be sent to a particular device(device token is not unique for all apps in a same device) or not.