var nodeList = document.getElementsByClassName('draggable');

for(var i=0;i<nodeList.length;i++) {
    var obj = nodeList[i];
    obj.addEventListener('touchmove', function(event) {

      var touch = event.targetTouches[0];
      var izq = document.getElementById('mano_izq');
      alert(izq.offsetLeft);
      var ancho = obj.offsetWidth;
      var alto = obj.offsetHeight;
      event.target.style.left = touch.pageX-(ancho/2) + 'px';
      event.target.style.top = touch.pageY-(alto/2) + 'px';
      event.preventDefault();
  }, false);
}

/*
var obj = document.getElementById('d1');
obj.addEventListener('touchmove', function(event) {
  // If there's exactly one finger inside this element
  if (event.targetTouches.length == 1) {
    var touch = event.targetTouches[0];
    // Place element where the finger is
    obj.style.left = touch.pageX-40 + 'px';
    obj.style.top = touch.pageY-40 + 'px';
  }
  event.preventDefault();
}, false);
*/

var nodeList = document.getElementsByClassName('draggable');

for(var i=0;i<nodeList.length;i++) {
    var obj = nodeList[i];
    obj.addEventListener('touchmove', function(event) {

      var touch = event.targetTouches[0];
      var izq = document.getElementById('mano_izq');
      var ancho = obj.offsetWidth;
      var alto = obj.offsetHeight;
      event.target.style.left = touch.pageX-(ancho/2) + 'px';
      event.target.style.top = touch.pageY-(alto/2) + 'px';
      if (event.target.style.top === (izq.offsetLeft)) {
        alert(izq.offsetLeft);
      }
      event.preventDefault();
  }, false);
}

/*
var obj = document.getElementById('d1');
obj.addEventListener('touchmove', function(event) {
  // If there's exactly one finger inside this element
  if (event.targetTouches.length == 1) {
    var touch = event.targetTouches[0];
    // Place element where the finger is
    obj.style.left = touch.pageX-40 + 'px';
    obj.style.top = touch.pageY-40 + 'px';
  }
  event.preventDefault();
}, false);
*/

Update app.js