<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>回到顶部</title>
<style>
#to_top {
width: 30px;
height: 40px;
font: 14px/20px arial;
text-align: center;
background: #06c;
position: fixed;
cursor: pointer;
color: #fff;
left: 1250px;
top: 500px;
}
</style>
</head>
<body style="height: 2000px;">
<div id="to_top">返回顶部</div>
<script src="jquery-1.10.1.js"></script>
<script>
$(function () {
// 运动总时长
var time = 300
// 每一帧动画的执行时间
var itemTime = 60
// 启动定时器 执行动画
$('#to_top').click(function(){
var offset = $('html').scrollTop() + $('body').scrollTop();
var itemOffset = offset/(time/itemTime);
var timer = setInterval(function(){
offset -= itemOffset;
if(offset <= 0){
offset = 0;
clearInterval(timer);
}
console.log(offset);
$('html,body').scrollTop(offset);
},itemTime)
})
});
</script>
</body>
</html>
