iframe截取网站部分内容实现思路及代码

<div style="width:630px;height:350px;overflow:hidden;border:0px"> 
<div style="width:800px;height:800px;margin:-810px 0px 0px -10px;"> 
<iframe src="http://www.sci99.com/" width="960" height="1280" scrolling="no"></iframe> 
</div> 
</div> 
<div style="width:800px;height:900px;overflow:hidden;border:0px"> 
<div style="width:500px;height:900px;margin:-320px 0px 0px -10px;"> 
<iframe src="http://www.sci99.com/details/monitorall.aspx" width="700" height="1024" scrolling="no"></iframe> 
</div> 
</div>