最近几天做了一个项目，原来是用css3动画做的，由于不兼容IE，改成用js做了，特此分享给大家，供大家参考，代码有bug欢迎提出，写的不好还请见谅!
<!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" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
<title>float left and top</title>
<style type="text/css">
.w1000{position:relative;width:1000px;margin:0 auto;}
.positionpub{position:absolute;}
.positionpub p{width:50px;height:50px;background:#333;color:#fff;line-height:50px;text-align:center;position:absolute;}
.ad_Float{top:50px;left:50px;}
.ad_Float1{top:150px;left:250px;}
.ad_Float2{top:250px;left:450px;}
</style>
</head>
<body>
<div class="w1000">
<div class="ad_Float positionpub">
<p id="ad_Float">left</p>
</div>
<div class="ad_Float1 positionpub">
<p id="ad_Float1">right</p>
</div>
<div class="ad_Float2 positionpub">
<p id="ad_Float2">down</p>
</div>
</div>
<script type="text/javascript">
var x = 0, y = 0 , x1 = 0;
var xin = true, yin = true;
var step = 1,step2 = 2;
var delay = 10;
var obj = document.getElementById("ad_Float");
var obj1 = document.getElementById("ad_Float1");
var obj2 = document.getElementById("ad_Float2");
function ad_Float() {
var L = 0;
var R = 100;
obj.style.left = x + document.documentElement.scrollLeft + "px";
x = x + step * (xin ? 1 : -1);
if (x < L) {
xin = true;
x = L;
}
if (x > R) {
xin = false;
x = R;
}
};
function ad_Float1() {
var L1 = 0;
var R1 = 100;
obj1.style.left = x1 + document.documentElement.scrollLeft + "px";
x1 = x1 + step * (xin ? 1 : -1);
if (x1 < L1) {
xin = true;
x1 = L1;
}
if (x1 > R1) {
xin = false;
x1 = R1;
}
};
function ad_Float2() {
var T = 0;
var B = 150;
obj2.style.top = y + document.documentElement.scrollTop + "px";
y = y + step2 * (yin ? 1 : -1);
if (y < T) {
yin = true;
y = T;
}
if (y > B) {
yin = false;
y = B;
}
};
var itl = setInterval("ad_Float()", delay);
var itl1 = setInterval("ad_Float1()", delay);
var itl2 = setInterval("ad_Float2()", delay);
</script>
</body>
</html>
代码到此结束了，希望对大家有所帮助！