为什么我的页面顶部按钮在我的 API 应用程序上滚动到顶部然后返回时会卡顿/滞后/粘滞，但在网页上却正常运行？

Question

So I have an API that I added a top of page button to. The button works fine on mobile and desktop on 2 webpages I built but for my API apps (this one especially) it lags/stutters/sticks when I get down to mobile screen sizes. Take a look at my screen shot and here is the code:

      <!--Top of Page Button-->
    <div  class="top_link_position">
      <a  class="back-to-top" href="#page_top" title="Top">
      <button class="top_btn">
       <i class="fas fa-arrow-up fa-3x"></i>

       
      </button>
      </a>
  </div>

    .top_link_position {
  display: block;
position: fixed;
  bottom: 4%;
  right: 3%;
  z-index: 600;
}


.top_btn {
    border: 1.5px solid white;
    background: #db0606;
    padding: .5rem .5rem;
    color: white;
    font-weight: bolder;
    text-transform: uppercase;
}

$(document).ready(function () {
   $(window).scroll(function () {
      if ($(this).scrollTop() > 100) {
         $('.back-to-top').fadeIn();
      } else {
         $('.back-to-top').fadeOut();
      }
   });

   $('.back-to-top').click(function () {
      $("html, body").animate({
         scrollTop: 0
      }, 100);
      return false;
   });

});

Answer 1

The only solution I found was getting another button and code from a different source. A lot of these you find on google don't seem to work.