滚动获取距离
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
*{padding: 0;margin: 0;}
.header{
width:100%;
height: 200px;
background-color: #000;
}
.nav{
width:100%;
height: 300px;
background-color: #f5f5f5;
}
.conter{
width:100%;
height: 1800px;
background-color: pink;
}
.footer{
width:100%;
height:200px;
background-color:#ccc;
}
#toTop{
position: fixed;
bottom: 100px;
right: 50px;
width: 50px;
height: 30px;
text-align: center;
background-color: #fff;
display: none;
}
</style>
</head>
<body>
<div class="header">header</div>
<div class="nav">nav</div>
<div class="conter">内容</div>
<div class="footer">页脚</div>
<div id="toTop" onclick="goTop()">top</div>
</body>
<script type="text/javascript">
window.onscroll=function(){
var st=document.documentElement.scrollTop;
var wh=window.innerHeight;
// console.log(st,wh);
if(st>wh){
toTop.style.display="block";
}
else{
toTop.style.display="none";
}
}
function goTop(){
var st =document.documentElement.scrollTop;
var id=setInterval(function(){
var now= document.documentElement.scrollTop;
document.documentElement.scrollTop=now-(st/10);
console.log("now:",now,"st/10:",st/10,"st:",st)
if(now-(st/10)<=0){
clearInterval(id);
}
},100)
}
</script>
</html>
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