简单浮动层效果问题

<script language=javascript>
function AAP(){
   var content="<TABLE BORDER=1 CELLPADDING=2 CELLSPACING=1 bgcolor=#00ff00><TR><TD bgcolor=#FFFFFF ><img src=f02.gif></TD></TR></TABLE>"; 
   document.all("skn2").innerHTML=content;
         skn2.style.visibility="visible";
         var x=dd.style.left;
         var y=dd.style.top;
         if ((x - document.body.scrollLeft) > 650) {
             x = x - 135;
         } else { x = x -2;}         if ((y - document.body.scrollTop) > 370) {
             y = y - 223;
         } else { y = y + 2;}
         skn2.style.posLeft= x;
         skn2.style.posTop = y;
       }
</script>
</head>
<body><A style="POSITION: absolute; LEFT: 433; TOP: 475; visibility:visible"  onmouseover="AAP()" onmouseout="skn2.style.visibility='hidden';" id="dd">中国金融中心</A><div style="position:relative; width: 100px; height: 100px; z-index: 1;" id="skn2">
</div>