我觉得定位布局比较好实现，如果用浮动布局 模块内容增多的话 这个混合布局就乱了 下面是我实现的代码 对任务3 4有点迷
<!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>混合布局编程挑战</title>
<style type="text/css">
body{ margin:0; padding:0; font-size:30px; color:#fff}
.top{height:200px; background:#ccc;}
.main{height:800px;background:red;margin:0 auto;}
.right{height:800px;width:100%;background:green;position:absolute;left:210px;}
.left{ height:800px;width:200px;background:blue;posotion:absolute}
.foot{height:100px;background:orange;}
</style>
</head>
<body>
<div class="top">top</div>
<div class="main">
<div class="right">right</div>
<div class="left">left</div>
</div>
<div class="foot">foot</div>
</body>
</html>
