代码很简单，这里就不多废话了，小伙伴们看代码吧。
HTML：
CSS：
.fl{
display:block;
float:left;
width:50px;
height:50px;
text-align:center;
background-color:#eaeaea;
background-image:url(../images/toTop.png);
}
.fl:hover{background-color:#f48942;background-image:url(../images/toTop.png);}
#Fixed {
position: fixed;
_position: absolute;
z-index: 100;
bottom: 70px;
left: 50%;
margin-left: 530px;
_bottom: auto;_top:
expression(document.documentElement.scrollTop+document.documentElement.clientHeight-this.offsetHeight-70);
width: 50px;
text-indent: -40000px;
background: #fff
}
/*置顶 end*/
Js：
/*置顶功能*/
$(function(){
$(window).bind('scroll', {
fixedOffsetBottom: parseInt($('#Fixed').css('bottom'))
},
function(e) {
var scrollTop = $(window).scrollTop();
var referFooter =$('#footer');
scrollTop > 100 ? $('#goTop').show() : $('#goTop').hide();
if (!/msie 6/i.test(navigator.userAgent)) {
if ($(window).height() - (referFooter.offset().top - $(window).scrollTop()) > e.data.fixedOffsetBottom) {
$('#Fixed').css('bottom', $(window).height() - (referFooter.offset().top - $(window).scrollTop()))
} else {
$('#Fixed').css('bottom', e.data.fixedOffsetBottom)
}
}
});
$('#goTop').click(function() {
$('body,html').stop().animate({
'scrollTop': 0,
'duration': 100,
'easing': 'ease-in'
})
});
});
/*置顶功能 end*/
