text: const backToTop = document.querySelector("#back-to-top-btn");
  let page = window.pageYOffset;
  page = 0;
  window.addEventListener("scroll", page, scrollFunction);
  //backToTop.addEventListener("none");
  
  function scrollFunction() {
  
    //using pageYOffSet for allow all browser
    if (window.pageYOffset > 2000) {
      backToTop.style.display = "block";
    } else {
      backToTop.style.display = "none";
    }
  }
  backToTop.addEventListener("click", toTop);
  
  function toTop() {
    window.scrollTo(0, 0);
  }
  