ap.showNavigationBarLoading()

<script src="https://gw.alipayobjects.com/as/g/h5-lib/alipayjsapi/3.1.1/alipayjsapi.inc.min.js"></script>

<button id="J_btn_show" class="btn btn-default">showNavigationBarLoading</button>
<button id="J_btn_hide" class="btn btn-default">hideNavigationBarLoading</button>
<script>
  var btnShow = document.querySelector('#J_btn_show');
  var btnHide = document.querySelector('#J_btn_hide');
  btnShow.addEventListener('click', function(){
    ap.showNavigationBarLoading();
  });
  btnHide.addEventListener('click', function(){
    ap.hideNavigationBarLoading();
  });
</script>