5.FF1.5测试通过，绝对定位，边距为比例，此时容器高宽始终为viewport的50%相对大小（标准）：
<div style="position:absolute; top:0; right:0; bottom:0; left:0; width:50%; height:50%; margin:auto; background:#f00; color:white; line-height:20px; text-align:center;">FF1.5测试通过</div>
6.FF1.5测试通过，绝对定位，直接定位上下左右，强制边局实现容器相对大小（标准）：
代码：略
7.ff1.5 IE5 IE6通过测试
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "//www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="//www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Vertical centering in valid CSS</title>
<style type="text/css">
body {padding: 0; margin: 0; font-size: 75%; line-height: 140%; font-family:Arial, Helvetica, sans-serif;}
body,html{height: 100%; }
a{color: #333;}
a:hover{color: green;}
#outer {height: 100%; overflow: hidden; position: relative;width: 100%; background:ivory; }
#outer[id] {display: table; position: static;}
#middle {position: absolute; top: 50%;text-align:center;} /* for explorer only*/
#middle[id] {display: table-cell; vertical-align: middle; position: static;}
#inner {position: relative; top: -50%;width: 600px;margin: 0 auto;text-align:left;}/*for explorer only */
div.greenBorder {border: 1px solid green; background-color: #FFF;}
p{margin: 1em;}
</style>
<script type="text/javascript">
// <![CDATA[
function toggleContent(name,n) {
var i,t='',el = document.getElementById(name);
if (!el.origCont) el.origCont = el.innerHTML;
for (i=0;i<n;i++) t += el.origCont;
el.innerHTML = t;
}
// ]]>
</script>
</head>
<body>
<div id="outer">
<div id="middle">
<div id="inner" class="greenBorder">
<p><a href="javascript:toggleContent('inner',1)">默认长度</a> <a href="javascript:toggleContent('inner',2)">加长页面</a></p>
<p> 1.打开illustrator,新建一个文件，画个矩形，比你要导入的图片大一些，白色填充。 <br />
2.选中矩形，菜单：Effect > Distort & Transform > Zig Zag，设置如下图。 <br />
3.菜单：Effect > Stylize > Drop Shadow，设置如下图。 <br />
1.打开illustrator,新建一个文件，画个矩形，比你要导入的图片大一些，白色填充。 <br />
2.选中矩形，菜单：Effect > Distort & Transform > Zig Zag，设置如下图。 <br />
3.菜单：Effect > Stylize > Drop Shadow，设置如下图。</p>
<address style="text-align:center; padding: .5em; clear: left;">
Design by <a href="//www.jzxue.com">jzxue</a> 本演示采用<a href="//www.creativecommons.cn/">创作共用授权</a>--署名和非商业用途。
</address>
</div>
</div>
</div>
<script src="//www.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
_uacct = "UA-152060-1";
urchinTracker();
</script>
<noscript><p>google-analytics</p></noscript>
<script src="//www.jzxue.com/*/*.js" type="text/javascript"></script>
<noscript><p>stat.</p></noscript>
</body>
</html>
8.利用expression(仅对IE)
<div style="background:blue;position:absolute;left:expression((body.clientWidth-50)/2);top:expression((body.clientHeight-50)/2);width:50;height:50"></div>
