Login with Facebook API V2

function fb_login(){
  FB.login(function(response) {
      if (response.authResponse) {
          console.log('Welcome!  Fetching your information.... ');
          //console.log(response); // dump complete info
          access_token = response.authResponse.accessToken; //get access token
          user_id = response.authResponse.userID; //get FB UID

          FB.api('/me?fields=id,name,friendlists', function(response) {
              user_email = response.email; //get user email
              console.log(response);
              alert(user_email);
        // you can store this data into your database
          });

      } else {
          //user hit cancel button
          console.log('User cancelled login or did not fully authorize.');

      }
  }, {
      scope: 'publish_stream,email,read_friendlists'
  });
}