div层的固定位置浮动

<style>
.fixed
{
right:10px;
top:100px;
width:100px;
height:500px;
background:#009999;
border:#336699 1px dashed;
+position:absolute;
+top:expression(eval(document.body.scrollTop)+100);
}
</style>
<div class=fixed></div>
<div style=height:1000px></div>