Jquery on scroll Animation

var btn = $(“#back-top”);

$(window).scroll(function () {
$(this).scrollTop() > 100 ? btn.fadeIn() : btn.fadeOut();
});

btn.click(function () {
$(“body,html”).animate({
scrollTop: 0
}, 1000);
$(“.rocket”).addClass(“fly”);

setTimeout(function () {
$(“.rocket”).removeClass(“fly”);
}, 1000);

return false;
});

const funs = new Funs();
funs.signature();