网上一大堆了,自己做个笔记。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css">
.content{
margin:0 auto;
width:980px;
height:3600px;
background:#000;
}
#top{
position:fixed;
left:50%;
margin-left:500px;
width:40px;
height:40px;
background:#F00;
display:none;
bottom:10px;}
#top:hover{
background:#0FF;
}
</style>
<script src="https://cdn.bootcss.com/jquery/1.11.3/jquery.min.js"></script>
<!--<script type="text/javascript">
window.onload=function(){
var isTop=true;
var top=document.getElementById("top");
var timer=null;
var clientHight=document.documentElement.clientHeight;
window.onscroll=function(){
var osTop=document.documentElement.scrollTop || document.body.scrollTop;
if(osTop>=clientHight){
top.style.display="block";
}else{
top.style.display="none";
}
if(!isTop){
clearInterval(timer);
}
isTop=True;
}
top.onclick=function(){
timer=setInterval(function(){
var osTop=document.documentElement.scrollTop || document.body.scrollTop;
var ispeed=Math.floor(-osTop/6);
document.documentElement.scrollTop=document.body.scrollTop=osTop+ispeed;
isTop=true;
if(osTop==0){
clearInterval(timer);
}
},30);
}
}
</script>--->
<script>
$(function(){
//当滚动条的位置处于距顶部100像素以下时,跳转链接出现,否则消失
$(function () {
$(window).scroll(function(){
if ($(window).scrollTop()>100){
$("#top").fadeIn(1500);
}
else
{
$("#top").fadeOut(1500);
}
});
//当点击跳转链接后,回到页面顶部位置
$("#top").click(function(){
$('body,html').animate({scrollTop:0},300);
return false;
});
});
});
</script>
<title>无标题文档</title>
</head>
<div class="content"></div>
<div id="top"></div>
<body>
</body>
</html>