//Get the button: mybutton = document.getElementById(“myBtn”);
// When the user scrolls down 20px from the top of the document, show the button window.onscroll = function() {scrollFunction()};
function scrollFunction() {
if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) { alert('yes'); mybutton.style.display = "block"; } else { mybutton.style.display = "none"; alert('yes'); }
}
// When the user clicks on the button, scroll to the top of the document function topFunction() {
document.body.scrollTop = 0; // For Safari document.documentElement.scrollTop = 0; // For Chrome, Firefox, IE and Opera
}