<div style="position:absolute;top:500px;left:60px;height:2000px;background-color:yellow;">
This tall div is absolutely positioned 500 pixels from the top and 60 pixels from the left of its containing block.
</div>
<div style="position:fixed;top:100px;left:60px;180px;background-color:red;">
This div is using a fixed position of 100 pixels from the top and 60 pixels from the left of its containing block. When this page scrolls, this box will remain in a fixed position - it won't scroll with the rest of the page. Go on - SCROLL!
</div>
效果：
http://www.cnblogs.com/0banana0/archive/2011/05/25/2056662.html
