网站首页漂浮窗口的代码

<div id="ad" style="position:absolute"><a href=http://www.sunsprite.net target="_blank"><img src="img01.gif" border="0"></a></div> 
<script> 
var x = 50,y = 60 
var xin = true, yin = true 
var step = 1 
var delay = 10 
var obj=document.getElementById("ad") 
function floatAD() { 
var L=T=0 
var R= document.body.clientWidth-obj.offsetWidth 
var B = document.body.clientHeight-obj.offsetHeight 
obj.style.left = x + document.body.scrollLeft 
obj.style.top = y + document.body.scrollTop 
x = x + step*(xin?1:-1) 
if (x < L) { xin = true; x = L} 
if (x > R){ xin = false; x = R} 
y = y + step*(yin?1:-1) 
if (y < T) { yin = true; y = T } 
if (y > B) { yin = false; y = B } 
} 
var itl= setInterval("floatAD()", delay) 
obj.onmouseover=function(){clearInterval(itl)} 
obj.onmouseout=function(){itl=setInterval("floatAD()", delay)} 
</script> 

代码分析： <div id="ad" style="position:absolute"><a href=http://www.sunsprite.net target="_blank"><img src="img01.gif" border="0"></a></div> 
<script> 
var x = 50,y = 60 //浮动层的初始位置，分别对应层的初始X坐标和Y坐标 
var xin = true, yin = true //判断层的X坐标和Y坐标是否在在控制范围之内，xin为真是层向右移动，否则向左；yin为真是层向下移动，否则向上 
var step = 1 //层移动的步长，值越大移动速度越快 
var delay = 10 //层移动的时间间隔,单位为毫秒，值越小移动速度越快 
var obj=document.getElementById("ad") //捕获id为ad的层作为漂浮目标 
function floatAD() { 
var L=T=0 //层移动范围的左边界(L)和上边界(T)坐标