gistfile1.txt

javascript:(function(){
var loader = function(url,cb) {
  var script = document.createElement('script');
  script.setAttribute('type', 'text/javascript');
  script.setAttribute('src', url);
  script.onload = script.onreadystatechange = function() {
    if (!this.readyState ||
        this.readyState === 'loaded' ||
        this.readyState === 'complete') {
      setTimeout(function(){
        cb();
      },0);
      script.onload = script.onreadystatechange = null;
    }
  };

  document.body.insertBefore(script, document.body.childNodes[0]);
};
loader('http://hikejun.com/tmp/headtrackr.min.js',function(){var compare = document.createElement('canvas');
compare.style.cssText = 'position:absolute;left:-1000em;top:-1000em;';
compare.width = 320;
compare.height = 240;
document.body.appendChild(compare);
var video = document.createElement('video');
video.style.cssText = 'position:absolute;left:-1000em;top:-1000em;';
document.body.appendChild(video);
var ht = new headtrackr.Tracker({calcAngles: true, ui: false, headPosition: false});
ht.init(video, compare);
ht.start();
document.addEventListener('headtrackrStatus', function (e) {
  console.log(e.status);
});
var ops=[];
document.addEventListener('facetrackingEvent', function (e) {
    var angle = (Math.PI/2) - e.angle;
    if (angle > 0.3) {
      if(ops.length == 1) {
        ops.push(1);
      }
    } else if(angle < -0.3) {
      if(ops.length == 1) {
        ops.push(2);
      }
    } else {
      if (ops.length > 1 && ops.join('') == '01') {
        window.scrollBy(0, window.innerHeight);
      } else if(ops.length > 1 && ops.join('') == '02') {
        window.scrollBy(0, -window.innerHeight);
      }
      ops = [0];
    }
});
});
})();