title: find out how many friends accepted my App invitation using phonegap?
body: <p>i have an App which is developed with Phonegap/Cordova.</p>
  
  <p>i want to add the functionality:<br>
  <strong>if the user invites x friends and they installed the app, then user gets x points</strong>.<br>
  if it is not possible then i guess i can live with:<br>
  <strong>if the user invites x friends, then user gets x points</strong>.</p>
  
  <p>the user can invite friends over facebook, Whatsapp, (Email)</p>
  
  <p>my questions are:</p>
  
  <ol>
  <li>is there away to achieve this "ensure invited and installed"
  functionality?</li>
  <li>i have seen the Facebook Api provides a similar functionality, what about WhatsApp?, or Email?</li>
  </ol>
  
  <p>Thank you for your hints</p>