function addNavigation(num) {
  var link =
    '<span class="nav"><a href="javascript:void(0)" id="nav' + num + '">' + DEVICE_LIST[num] + '</a>&emsp;</span>';
  $('#js-nav').append(link);
  var nav_id = '#nav' + num;
  $(nav_id).click(function () {
    var label_id = '#label' + num;
    scrollToElement(label_id);
  });
}

function scrollToElement(id) {
  var rect = $(id)[0].getBoundingClientRect();
  var etop = rect.top + window.pageYOffset;
  $(window).scrollTop(etop);
  //$('html,body').animate({ scrollTop: etop }, 600);
}