Question

I see this fiddle sample here

I want when “to the top” appear, an click! should scroll to the top smoothly or slow

$(window).scroll(function() {
    if ($(this).scrollTop()) {
        $('#toTop').fadeIn();
    } else {
        $('#toTop').fadeOut();
    }
});

Answer 1

$("#toTop").click(function () {
   //1 second of animation time
   //html works for FFX but not Chrome
   //body works for Chrome but not FFX
   //This strange selector seems to work universally
   $("html, body").animate({scrollTop: 0}, 1000);
});

http://jsfiddle.net/fjXSq/161/