<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>03_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 () {
//回到顶部
$('#to_top').click(function () {
var $body = $(document.body)
var $html = $(document.documentElement)
//使用scrollTop(): 瞬间滚动到顶部
// $('html,body').scrollTop(0)
//使用scrollTop(): 平滑滚动到顶部
var offset = $body.scrollTop() + $html.scrollTop()
if(offset===0) {
return
}
var totalTime = 300
var intervalTime = 30
var itemOffset = offset/(totalTime/intervalTime)
var intervalId = setInterval(function () {
offset -= itemOffset
if(offset<=0) {
offset = 0
clearInterval(intervalId)
}
$('html,body').scrollTop(offset)
}, intervalTime)
//使用动画: 平滑滚动到顶部
// $('body,html').animate({scrollTop:0},300)
})
});
</script>
</body>
</html>
展示
