Spotify Web API - Display User Data

Fetches information about the logged in user and displays it

HTML

<link rel="stylesheet" href="https://developer.spotify.com/web-api/static/css/cached.css">
<script src="http://cdnjs.cloudflare.com/ajax/libs/handlebars.js/2.0.0-alpha.1/handlebars.min.js"></script>
<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<div class="container">
   
    <input type="text" id="playlist-uri" value="spotify:user:spotify:playlist:1Hd6FKA6On582nMsfpoRTl"></input>
    </p>
    <button class="btn btn-primary" id="btn-follow">Follow</button>
</div>

CSS

input {
    width: 400px;
}

JavaScript

(function() {
    
    function login(callback) {
        var CLIENT_ID = '6b284830006843e7ae7b170725715aed';
        var REDIRECT_URI = 'http://jmperezperez.com/spotify-oauth-jsfiddle-proxy/';
        function getLoginURL(scopes) {
            return 'https://accounts.spotify.com/authorize?client_id=' + CLIENT_ID +
              '&redirect_uri=' + encodeURIComponent(REDIRECT_URI) +
              '&scope=' + encodeURIComponent(scopes.join(' ')) +
              '&response_type=token';
        }
        
        var url = getLoginURL([
            'playlist-modify-public'
        ]);
        
        var width = 450,
            height = 730,
            left = (screen.width / 2) - (width / 2),
            top = (screen.height / 2) - (height / 2);
    
        window.addEventListener("message", function(event) {
            var hash = JSON.parse(event.data);
            if (hash.type == 'access_token') {
                callback(hash.access_token);
            }
        }, false);
        
        var w = window.open(url,
                            'Spotify',
                            'menubar=no,location=no,resizable=no,scrollbars=no,status=no, width=' + width + ', height=' + height + ', top=' + top + ', left=' + left
                           );
        
    }

    function followPlaylist(accessToken, playlistUri) {
        var parts = playlistUri.split(':');
        $.ajax({
            url: 'https://api.spotify.com/v1/users/' + parts[2] + '/playlists/' + parts[4] + '/followers',
            headers: {
               'Authorization': 'Bearer ' + accessToken
            },
            method: 'PUT',
            success: function() {
                followButton.textContent = 'Following';
            },
            dataType: 'html',
            error: function(e) {
                console.error(e);
            }
        });
    }

    var followButton = document.getElementById('btn-follow'),
        playlistUriInput = document.getElementById('playlist-uri');
 ...