lnapp/media/theme/baseadmin/js/backtotop.js

$(document).ready(function() {
	var backToTop = $('<a>', { id: 'back-to-top', href: '#top' });
	var icon = $('<i>', { class: 'fa fa-chevron-up' });

	backToTop.appendTo ('body');
	icon.appendTo (backToTop);

	backToTop.hide();

	$(window).scroll(function () {
		if ($(this).scrollTop() > 100) {
			backToTop.fadeIn ();
		} else {
			backToTop.fadeOut ();
		}
	});

	backToTop.click (function (e) {
		e.preventDefault ();

		$('body, html').animate({
			scrollTop: 0
		}, 600);
	});
});