返回顶部按钮响应滚动且动态显示与隐藏

156 阅读 0 评论 103 点赞

我是靠谱客的博主怕黑曲奇，最近开发中收集的这篇文章主要介绍返回顶部按钮响应滚动且动态显示与隐藏，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

很多的网站上都有返回顶部功能，判断滚动参数动态显示与隐藏，比较适合初学者

<!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" />
<title>实现动态的显示回到顶部与否</title>
<style>
/*返回顶部*/
.back_top {width:45px;height:45px;background:url(back_top_new.png) 0 0;position:fixed;left:50%;margin-left:500px;bottom:105px;display:none;}
.back_top:hover{background:url(images/back_top_new.png) 0 -46px;}
</style>
</head>

<body>
<a title="返回顶部" href="javascript：void(0)" class="back_top"></a>
<script src="js/jquery-1.11.0.min.js"></script>
<script>
var mousewheelevt=(/Firefox/i.test(navigator.userAgent))? "DOMMouseScroll" : "mousewheel"; //FF doesn't recognize mousewheel as of FF3.x
if (document.attachEvent) //if IE (and Opera depending on user setting)
document.attachEvent("on"+mousewheelevt, function(e){
var t=document.body.scrollTop+document.documentElement.scrollTop;
if(t==0){
$(".back_top").css("display","none");
}
else{
$(".back_top").css("display","block");
}
});
else if (document.addEventListener) //WC3 browsers
document.addEventListener(mousewheelevt, function(e){
var t=document.body.scrollTop+document.documentElement.scrollTop;
if(t==0){
$(".back_top").css("display","none");
}
else{
$(".back_top").css("display","block");
}
}, false);

</script>
</body>
</html>