页面往下滚动后，一块DIV如果滚动到头后一直保持在最上面？
0
最佳答案
3
可以尝试用这样的代码：
z-index: auto;
position: fixed;
margin:.....以下就不用多说了吧！
奖励园豆：5
其他回答(1)
0
不能，如果只是想在页面上固定一个东西的位置，可以用position来实现，但他们这个，本来就在一个位置，向下滚动超过这个位置才会开始固定，必须要用到JS，下面是我精简过的这个页面，你可以试试看下：
View Code
<!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"/>
<style type="text/css">
.col1{width:620px;float:left;margin:23px 40px 20px 0; position:relative;}
.div1{}
.div2{position:fixed;_position:absolute;top:0;z-index:300;}
</style>
</head>
<body>
<div class="page">
<div class="col1">
<div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div>
<div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div>
<div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div>
<div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div><div>aa</div>
</div>
<div>bb</div>
<div id="float" class="div1">
ddddddddddddd
</div>
<script type="text/javascript">
window.onload=
function(){
var oDiv=document.getElementById("float");
var H=0;
var Y=oDiv;
while(Y){H+=Y.offsetTop;Y=Y.offsetParent};
window.onscroll=function()
{
var s=document.body.scrollTop||document.documentElement.scrollTop;
if(s>H){oDiv.className="div1 div2";}
else{oDiv.className="div1";}
};
}
</script>
</body>
</html>
