直接上DEMO了
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<style type="text/css">
<!--
.d1 {
position:absolute;
top:20px;
left:20px;
width:200px;
height:200px;
background:red
}
.d2 {
width:500px;
height:100px;
background:blue;
}
-->
</style>
<div class="d1"></div>
<div class="d2"></div>
