类似淘宝,当页面出现滚动条,点击回到顶部。 那个层先是隐藏的么?一出现滚动条他就出现了。如何实现的?回到顶部js 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 获取body的scrollTop,如果>0,因为有滚动条并且滚动了,scrollTop就是正数,就显示 那为什么当scrollTop>0时,回到顶部那个按钮,一直浮在在页面上? <!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></title> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js"></script> <script type="text/javascript"> var cW,cH; function scrolls() { cW = document.documentElement.clientWidth || document.body.clientWidth; cH = document.documentElement.clientHeight || document.body.clientHeight; var _div = document.createElement('div'); _div.className = 'divClass'; _div.appendChild(document.createTextNode('UP')); _div.id = 'divId'; _div.onclick = function() { //document.documentElement.scrollTop = '0'; var bodys = document.documentElement || document.body; var explorer = window.navigator.userAgent ; if(explorer.indexOf("Chrome") >= 0) { $(document.body).animate({scrollTop: '0'}, 100); } else { $(document.documentElement).animate({scrollTop: '0'}, 100); } document.getElementById('divId').style.display = 'none'; } //_div.setAttribute('onclick', function() { //document.documentElement.scrollTop = '0'; //document.getElementById('divId').style.display = 'none'; //}); document.body.appendChild(_div); document.getElementById('divId').style.left = (cW - 40) + 'px'; document.getElementById('divId').style.top = (cH - 40) + 'px'; } function shang() { var bodys = document.documentElement.scrollTop || document.body.scrollTop; if(bodys > 10) { document.getElementById('divId').style.display = 'block'; } else { document.getElementById('divId').style.display = 'none'; } } function resizediv() { cW = document.documentElement.clientWidth || document.body.clientWidth; cH = document.documentElement.clientHeight || document.body.clientHeight; var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft; var scrollTop = document.documentElement.scrollTop || document.body.scrollTop; document.getElementById('divId').style.left = (cW - 40 + scrollLeft) + 'px'; document.getElementById('divId').style.top = (cH - 40 + scrollTop) + 'px'; } window.onload = function() { scrolls(); } window.onresize = resizediv; window.onscroll = function() { shang(); resizediv(); } </script> <style type="text/css"> body { margin:0; padding:0; } .divClass { width:40px; height:40px; background-color:black; filter:alpha(Opacity=80);-moz-opacity:0.5;opacity: 0.5; position:absolute; color:red; text-align:center; cursor:pointer; display:none; } </style> </head> <body> <div style='height:1000px;'></div> </body> </html> 那为什么当scrollTop>0时,回到顶部那个按钮,一直浮在在页面上?那个按钮是个绝对定位,计算body的scollTop然后赋值给这个按钮css的top,他就浮动到页面上,随着滚动条滚动而它不动 js 新手求解 分享·CSDN 快速结贴给分 BookMarkLet 请教,这种日期选择方式该如何制作呢? 用js如何控制打印? jquery easyui布局问题 请大家推荐一款javascript混淆器 select动态创建的问题,谢谢 求一使图片产生百叶窗效果的代码 如何确定某个checkbox是否存在? 急!!!請大家幫忙看看這個問題??? 如何批量替换页面中的某些字符串信息 用json格式为下拉菜单提供数据
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js"></script>
<script type="text/javascript">
var cW,cH;
function scrolls() {
cW = document.documentElement.clientWidth || document.body.clientWidth;
cH = document.documentElement.clientHeight || document.body.clientHeight;
var _div = document.createElement('div');
_div.className = 'divClass';
_div.appendChild(document.createTextNode('UP'));
_div.id = 'divId';
_div.onclick = function() {
//document.documentElement.scrollTop = '0';
var bodys = document.documentElement || document.body;
var explorer = window.navigator.userAgent ;
if(explorer.indexOf("Chrome") >= 0) {
$(document.body).animate({scrollTop: '0'}, 100);
} else {
$(document.documentElement).animate({scrollTop: '0'}, 100);
}
document.getElementById('divId').style.display = 'none';
}
//_div.setAttribute('onclick', function() {
//document.documentElement.scrollTop = '0';
//document.getElementById('divId').style.display = 'none';
//});
document.body.appendChild(_div);
document.getElementById('divId').style.left = (cW - 40) + 'px';
document.getElementById('divId').style.top = (cH - 40) + 'px';
}
function shang() {
var bodys = document.documentElement.scrollTop || document.body.scrollTop;
if(bodys > 10) {
document.getElementById('divId').style.display = 'block';
} else {
document.getElementById('divId').style.display = 'none';
}
}
function resizediv() {
cW = document.documentElement.clientWidth || document.body.clientWidth;
cH = document.documentElement.clientHeight || document.body.clientHeight;
var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft;
var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
document.getElementById('divId').style.left = (cW - 40 + scrollLeft) + 'px';
document.getElementById('divId').style.top = (cH - 40 + scrollTop) + 'px';
}
window.onload = function() {
scrolls();
}
window.onresize = resizediv;
window.onscroll = function() {
shang();
resizediv();
}
</script>
<style type="text/css">
body { margin:0; padding:0; }
.divClass { width:40px; height:40px; background-color:black; filter:alpha(Opacity=80);-moz-opacity:0.5;opacity: 0.5; position:absolute; color:red; text-align:center; cursor:pointer; display:none; }
</style>
</head>
<body>
<div style='height:1000px;'></div>
</body>
</html>