Add an embedded spotify player that plays the track your currently listening to (or last listened to) Demo at http://orryb.com/projects/currentSpotify/

listenWithMe.js

var ListenWithMe = (function() {
    // Add your own config here
    var LASTFM_API_KEY = "";
    var LASTFM_USERNAME = "";
    // Element to inject the widget into
    var $playerWrapper = document.getElementById('spotify-player-wrapper');

    return {
        init: init
    }
    
    // Run this 
    function init() {
        getCurrentTrack().then(function(data) {
            var artist = data.artist['#text'];
            var track = data.name;
            return getTrackURI(artist, track);
        }).then(function(data) {
            $playerWrapper.innerHTML += buildSpotifyPlayer(data.uri);
        })
    }

    // Make a call to Last FM to get your latest played tracks;
    function getCurrentTrack() { 
        var url = "//ws.audioscrobbler.com/2.0/?method=user.getrecenttracks&user=" + LASTFM_USERNAME + "&api_key=" + LASTFM_API_KEY + "&format=json";
        
        return new Promise(function(resolve, reject) {
            var req = new XMLHttpRequest();
            req.open('GET', url);
            req.onload = function() {
                if (req.status == 200) {
                    var data = JSON.parse(req.response);
                    try {
                        resolve(data.recenttracks.track[0]);
                    } catch(err) {
                        reject(err);
                    }
                }
                else {
                    reject(Error(req.statusText));
                }
            };
            req.onerror = function() {
                reject(Error("Network Error"));
            };
            req.send();
        })
    }

    // Make a call to Spotify to search for the track and return the info
    function getTrackURI(artist, trackName) {
        var url = "//api.spotify.com/v1/search?q=track:" + trackName + "%20artist:" + artist + "&type=track"
        
        return new Promise(function(resolve, reject) {
            var req = new XMLHttpRequest();
            req.open('GET', url);
            req.onload = function() {
                if (req.status == 200) {
                    var data = JSON.parse(req.responseText);
                    try {
                        resolve(data.tracks.items[0]);
                    } catch(err) {
                        reject(err);
                    }
                }
                else {
                    reject(Error(req.statusText));
                }
            };
            req.onerror = function() {
                reject(Error("Network Error"));
            };
            req.send();
        })
    }

    // Returns an iframe with the track's URI
    function buildSpotifyPlayer(trackUri) {
        if(!trackUri) return;
        return '<iframe src="https://embed.spotify.com/?uri=' + trackUri + '" width="300" height="380" frameborder="0" allowtransparency="true"></iframe>';
    }
})();