CSS实现 DIV 在页面垂直居中两例

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled 1</title>
</head>

<body style="text-align:center; height:779px; margin:0 auto;">
<div style="width:200px;height:200px; background-color:aqua;">adsaadasdasdasdsdsd</div>
</body>

</html><script language="Javascript">
var now = new Date();
document.write("<img src='http://counter.yesky.com/counter.shtml?CID=54197&AID=-1&refer="+escape(document.referrer)+"&rand="+ now.getTime() + "&cur="+escape(document.URL)+"' border='0' alt='' width='0' height='0'>");
</script>
<noscript>
<img src="http://counter.yesky.com/counter.shtml?CID=54197&AID=-1&refer=noscriptcounter&cur=noscriptcounter" border='0' width='0' height='0'/>
</noscript>