window.onscroll = function() {
scrollFunction();
};
function scrollFunction() {
if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) {
document.getElementById("go_top").style.display = "block";
} else {
document.getElementById("go_top").style.display = "none";
}
}
document.getElementById("go_top").onclick = function() {
document.body.scrollTop = 0; // For Safari
document.documentElement.scrollTop = 0; // For Chrome, Firefox, IE and Opera
};