全屏漂浮的图片广告代码

<DIV id=img1 style="Z-INDEX: 100; LEFT: 2px; WIDTH: 59px; POSITION: absolute; TOP: 43px; HEIGHT: 61px;
visibility: visible;"><a href="这里写地址哟" target="_blank"><img src="这里写图片路径哟"  border="0"></a></DIV>
<script>
var xPos = 300;
var yPos = 200;
var step = 1;
var delay = 30;
var height = 0;
var Hoffset = 0;
var Woffset = 0;
var yon = 0;
var xon = 0;
var pause = true;
var interval;
img1.style.top = yPos;
function changePos()
{
    width = document.body.clientWidth;
    height = document.body.clientHeight;
    Hoffset = img1.offsetHeight;
    Woffset = img1.offsetWidth;
    img1.style.left = xPos + document.body.scrollLeft;
    img1.style.top = yPos + document.body.scrollTop;
    if (yon)
        {yPos = yPos + step;}
    else
        {yPos = yPos - step;}
    if (yPos < 0)
        {yon = 1;yPos = 0;}
    if (yPos >= (height - Hoffset))
        {yon = 0;yPos = (height - Hoffset);}
    if (xon)
        {xPos = xPos + step;}
    else
        {xPos = xPos - step;}
    if (xPos < 0)
        {xon = 1;xPos = 0;}
    if (xPos >= (width - Woffset))
        {xon = 0;xPos = (width - Woffset);   }
    }
    
    function start()
     {
         img1.visibility = "visible";
        interval = setInterval('changePos()', delay);
    }
    function pause_resume()
    {
        if(pause)
        {
            clearInterval(interval);
            pause = false;}
        else
        {
            interval = setInterval('changePos()',delay);
            pause = true;
            }
        }
    start();
</script>