<!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>无标题文档</title>
<style type="text/css">
#a1 { width:960px; height:560px; margin:0 auto;}
#a2{ width:300px; height:560px; float:left; margin-left:20px;}
#a5{ width:300px; height:560px; float:left; margin-left:20px; background-color:#FF1800; }
#a6{ width:300px; height:560px;margin-left:20px; float:right;}
#a3{ width:300px; height:270px; background-color:#00E7FF; margin-bottom:20px;}
//<span style="color: rgb(255, 0, 0); font-family: Arial, Helvetica, sans-serif;">margin-bottom:20px;</span><span style="color: rgb(255, 0, 0); font-family: Arial, Helvetica, sans-serif;">这里指的是与下面的div的距离</span>
#a4{ width:300px; height:270px; background-color:#FF27FF;}
#a7{ width:300px; height:170px; background-color:#00D800;}
#a8{ width:300px; height:170px; background-color:#6B16D2; margin-top:20px; margin-bottom:20px;}
<span style="color:#ff0000;">//<span style="font-family: Arial, Helvetica, sans-serif;">margin-top:25px; margin-bottom:25px;这里指的是与上面的和下面的div都是20px</span></span>
#a9{ width:300px; height:170px; background-color:#656A9B;}
</style>
<!--
letter-spacing:5px; 文字间距
overflow:hidden超过的部分显示方式
-->
</head>
<body>
<div id="a1">
<div id="a2">
<div id="a3"></div>
<div id="a4"></div>
</div>
<div id="a5"></div>
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<div id="a7"></div>
<div id="a8"></div>
<div id="a9"></div>
</div>
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</body>
</html>