code: function() {
        var elem = $(this);
        var data = window.kelmu.data[id];
        data.selectedElementNumber = parseInt(elem.attr('data-annotation'), 10);
        var elemData = data.definitions['step' + data.stepNumber][data.subStepNumber][data.selectedElementNumber];
        elemData.top = parseFloat(elem.css('top'));
        elemData.left = parseFloat(elem.css('left'));
  
        if (elem.hasClass('kelmu-annotation')) {
          elemData.height = elem.height();
          elemData.width = elem.width();
        }
      }
docs: Updates the position definition for the selected element.
  The function should be called so that `this` referes to the element.