图片显示十字交叉线，随鼠标移动效果

<style type="text/css">
#dv{position:relative;}
#linex{height:1px;width:300px;position:absolute;left:0px;background:#000;overflow:hidden;display:none;}
#liney{height:300px;width:1px;position:absolute;top:0px;background:#f00;overflow:hidden;display:none;}
</style>
<div id="dv"><img src="/imgblog/20120809/201208091413271901.gif" id="img"/><div id="linex"></div><div id="liney"></div></div>
<script>
window.onload=function(){
  var img=document.getElementById('img'),linex=document.getElementById('linex'),liney=document.getElementById('liney');
  linex.style.width=img.offsetWidth+'px';
  liney.style.height=img.offsetHeight+'px';
  document.getElementById('img').onmousemove=function(e){
     e=e||window.event;
     linex.style.display=liney.style.display='block';
     linex.style.top=(e.offsetY||e.layerY)+'px';
     liney.style.left=(e.offsetX||e.layerX)+'px';
  }
}
</script>