CSS

#scrolltoTop {
    text-align:center;
    position:fixed;
    bottom:15px;
    right:80px;
    cursor:pointer;
    display:none;
}

Letakkan kode CSS di atas tepat sebelum kode ]]></b:skin>

JavaScript

<script type='text/javascript'>
$(function () {
    $(window).scroll(function () {
        if ($(this).scrollTop() > 100) {
            $('#scrolltoTop').fadeIn();
        } else {
            $('#scrolltoTop').fadeOut();
        }
    });
    $('#scrolltoTop> img').click(function () {
        $('body,html').animate({
            scrollTop: 0
        }, 800).animate({
            scrollTop: 25
        }, 200).animate({
            scrollTop: 0
        }, 150).animate({
            scrollTop: 10
        }, 100).animate({
            scrollTop: 0
        }, 50);
    });
});
</script>

Letakkan kode JavaScript di atas tepat sebelum kode </head>

HTML

<div id='scrolltoTop'>
    <img alt='Back to top' src='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPpF84TaJlZyKSlTh_K4JP7FuoWiO_kclIBv9a9Z2y8l9nbfi9m5gg5Y9FQYDg5eaJCdLYYOEzoEyYy-TuogvVA0iQUswM3b2ykmJrnHOTqLBz8AEqAaRwF_941co8uOMr0GJsFDBoOe-c/s1600/Button-Upload-icon.png' title='Back To Top' />
</div>

Letakkan kode HTML di atas tepat sebelum kode </body>