Web Audio API resume from pause

Question

I often read that it's not possible to pause/resume audio files with the Web Audio API.
But now I saw a example where they actually made it possible to pause and resume it. I tried to figure out what how they did it. I thought maybe source.looping = falseis the key, but it wasn't.
For now my audio is always re-playing from the start.

This is my current code

var context = new (window.AudioContext || window.webkitAudioContext)();

function AudioPlayer() {
  this.source = context.createBufferSource();
  this.analyser = context.createAnalyser();
  this.stopped = true;
}

AudioPlayer.prototype.setBuffer = function(buffer) {
  this.source.buffer = buffer;
  this.source.looping = false;
};

AudioPlayer.prototype.play = function() {
  this.source.connect(this.analyser);
  this.analyser.connect(context.destination);

  this.source.noteOn(0);
  this.stopped = false;
};

AudioPlayer.prototype.stop = function() {
  this.analyser.disconnect();
  this.source.disconnect();
  this.stopped = true;
};

Does anybody know what to do, to get it work?

Answer 1

Oskar's answer and ayke's comment are very helpful, but I was missing a code example. So I wrote one: http://jsfiddle.net/v3syS/2/ I hope it helps.

var url = 'http://thelab.thingsinjars.com/web-audio-tutorial/hello.mp3';

var ctx = new webkitAudioContext();
var buffer;
var sourceNode;

var startedAt;
var pausedAt;
var paused;

function load(url) {
    var request = new XMLHttpRequest();
    request.open('GET', url, true);
    request.responseType = 'arraybuffer';
    request.onload = function() {
        ctx.decodeAudioData(request.response, onBufferLoad, onBufferError);
    };
    request.send();
};

function play() {
    sourceNode = ctx.createBufferSource();
    sourceNode.connect(ctx.destination);
    sourceNode.buffer = buffer;
    paused = false;

    if (pausedAt) {
        startedAt = Date.now() - pausedAt;
        sourceNode.start(0, pausedAt / 1000);
    }
    else {
        startedAt = Date.now();
        sourceNode.start(0);
    }
};

function stop() {
    sourceNode.stop(0);
    pausedAt = Date.now() - startedAt;
    paused = true;
};

function onBufferLoad(b) {
    buffer = b;
    play();
};

function onBufferError(e) {
    console.log('onBufferError', e);
};

document.getElementById("toggle").onclick = function() {
    if (paused) play();
    else stop();
};

load(url);