fb.js

var userID;
window.fbAsyncInit = function() {
  FB.init({
    appId      : '307079902999566',
    xfbml      : true,
    version    : 'v2.7'
  });
};
(function(d, s, id){
   var js, fjs = d.getElementsByTagName(s)[0];
   if (d.getElementById(id)) {return;}
   js = d.createElement(s); js.id = id;
   js.src = "//connect.facebook.net/en_US/sdk.js";
   fjs.parentNode.insertBefore(js, fjs);
 }(document, 'script', 'facebook-jssdk'));
// This is called with the results from from FB.getLoginStatus().

// Here we run a very simple test of the Graph API after login is
// successful.  See statusChangeCallback() for when this call is made.
function testAPI() {
  console.log('Welcome!  Fetching your information.... ');
  FB.api('/me', function(response) {
    console.log('Successful login for: ' + response.name);
    userID = response.userID;
});