回到顶点2方法

goto.js

/*goto top*/
.gotop{
	position: absolute;
    right: -148px;
    bottom: 30px;
    color: #000;
    width: 124px;
    z-index: 999;
}


// 回到顶部 bottom
	var hdFloat = $(".gotop");
  	$(window).scroll(function () { hdFloat.animate({ bottom: $(document).height() - $(window).height() - $(window).scrollTop() }, { queue: false, duration: 500 }) });

	$('.goto').on('click', function(){
	$('html,body').animate({
	  scrollTop: 0
	}, 'slow');
	return false;
	});
	
// 回到顶部 top
	var hdFloat = $(".gotop"),
		hdFloatTops = hdFloat.offset().top;
  	$(window).scroll(function () { hdFloat.animate({ top: $(window).scrollTop() + hdFloatTops }, { queue: false, duration: 500 }) });

	$('.goto').on('click', function(){
	$('html,body').animate({
	  scrollTop: 0
	}, 'slow');
	return false;
	});