<!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" />
<script type="text/javascript">
function opacity(id, opacStart, opacEnd, millisec) {
//speed for each frame
var speed = Math.round(millisec / 100);
var timer = 0;
//determine the direction for the blending, if start and end are the same nothing happens
if(opacStart > opacEnd) {
for(i = opacStart; i >= opacEnd; i--) {
setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
timer++;
}
} else if(opacStart < opacEnd) {
for(i = opacStart; i <= opacEnd; i++)
{
setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
timer++;
}
}
}
//change the opacity for different browsers
function changeOpac(opacity, id) {
var object = document.getElementById(id).style;
object.opacity = (opacity / 100);
object.MozOpacity = (opacity / 100);
object.KhtmlOpacity = (opacity / 100);
object.filter = "alpha(opacity=" + opacity + ")";
}
function shiftOpacity(id, millisec) {
//if an element is invisible, make it visible, else make it ivisible
if(document.getElementById(id).style.opacity == 0) {
opacity(id, 0, 100, millisec);
} else {
opacity(id, 100, 0, millisec);
}
}
function blendimage(divid, imageid, imagefile, millisec) {
var speed = Math.round(millisec / 100);
var timer = 0;
//set the current image as background
document.getElementById(divid).style.backgroundImage = "url(" + document.getElementById(imageid).src + ")";
//make image transparent
changeOpac(0, imageid);
//make new image
document.getElementById(imageid).src = imagefile;
//fade in image
for(i = 0; i <= 100; i++) {
setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed));
timer++;
}
}
function currentOpac(id, opacEnd, millisec) {
//standard opacity is 100
var currentOpac = 100;
//if the element has an opacity set, get it
if(document.getElementById(id).style.opacity < 100) {
currentOpac = document.getElementById(id).style.opacity * 100;
}
//call for the function that changes the opacity
opacity(id, currentOpac, opacEnd, millisec)
}
</script>
<title>Untitled Document</title>
</head>
<div style="width:100px;height:100px;background-image:url(img1.gif);">
<img src="img2.gif" width="100" height="100" id="MenuIMG" style="opacity:0;filter:alpha(opacity:0);" onmouseover="opacity('MenuIMG',0,100, 200)" onmouseout="opacity('MenuIMG',100,0, 200)" />
</div>
<body>
</body>
</html>
خوندم و تا تهش رفتم اما کار نکرد ... فکر کنم يه جا رو اشتباه رفتم ! 
يه سوال دیگه ! واسه اينکه کل اينها رو center کنم از اين کد استفاده کردم >
