<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/htmlcharset=gb2312" />
<title>无标题文档</title>
<script type="text/javascript">
function Zoom(obj,width, height)
{ var img=new Image()
img.src=obj.src
var scale=Math.max(width/img.width, height/img.height)
var newWidth=img.width*scale
var newHeight=img.height*scale
var div=obj.parentNode
obj.width=newWidth
obj.height=newHeight
div.style.width=width+"px"
div.style.height=height+"px"
div.style.overflow="hidden"
obj.style.marginLeft=(width-newWidth)/2+"px"
obj.style.marginTop=(height-newHeight)/2+"px"}
</script>
</head>
<body>
<div>
<img src="http://pic.hsw.cn/0/10/13/05/10130520_504118.jpg" onload="Zoom(this, 150, 100)" border="0" />
</div>
</body></html>
<div id=mydiv style="width:400pxheight:300pxborder:1px solid #000">请注意看这里的背景图是否居中</div><script>
window.onload=function() {
document.getElementById("mydiv").style.background="url(123.jpg) no-repeat center center"
}
</script>