鼠标滑过小图出现大图

<style>
#demo{overflow:hidden;width:120px;text-align:center;padding:10px;}
#demo img{border:none;width:100px;height:100px;border:5px solid #f4f4f4}
#enlarge_images{position:absolute;display:none;z-index:2;border:5px solid #f4f4f4}
</style>
<div id="demo" style="overflow:hidden;width:120px;text-align:center;padding:10px">
 <img src="http://www.51flash.cn/attachment/1182346916_0.jpg">
</div>
<div id="enlarge_images"></div>
<script>
var demo = document.getElementById("demo");
var gg = demo.getElementsByTagName("img");
var ei = document.getElementById("enlarge_images");
for(i=0; i<gg.length; i++){
 var ts = gg[i];
 ts.onmousemove = function(event){
  event = event || window.event;
  ei.style.display = "block";
  ei.innerHTML = '<img src="' + this.src + '" />';
  ei.style.top  = document.body.scrollTop + event.clientY + 10 + "px";
  ei.style.left = document.body.scrollLeft + event.clientX + 10 + "px";
 }
 ts.onmouseout = function(){
  ei.innerHTML = "";
  ei.style.display = "none";
 }
 ts.onclick = function(){
  window.open( this.src );
 }
}
</script>