body { margin: 0px; padding: 0px; text-align: center; }
#content { margin-left:auto; margin-right:auto; width: 400px; width: 370px; }  

两行一列

body { margin: 0px; padding: 0px; text-align: center;}
#content-top { margin-left:auto; margin-right:auto; width: 400px; width: 370px;}
#content-end {margin-left:auto; margin-right:auto; width: 400px; width: 370px;}

三行一列

body { margin: 0px; padding: 0px; text-align: center; }
#content-top { margin-left:auto; margin-right:auto; width: 400px; width: 370px; }
#content-mid { margin-left:auto; margin-right:auto; width: 400px; width: 370px; }
#content-end { margin-left:auto; margin-right:auto; width: 400px; width: 370px; }  

单行两列

#bodycenter { width: 700px;margin-right: auto; margin-left: auto;overflow: auto; }
#bodycenter #dv1 {float: left;width: 280px;}
#bodycenter #dv2 {float: right;width: 410px;}  

两行两列

#header{ width: 700px; margin-right: auto;margin-left: auto; overflow: auto;}
#bodycenter { width: 700px; margin-right: auto; margin-left: auto; overflow: auto; }
#bodycenter #dv1 { float: left; width: 280px;}
#bodycenter #dv2 { float: right;width: 410px;}

三行两列

#header{ width: 700px;margin-right: auto; margin-left: auto; }
#bodycenter {width: 700px; margin-right: auto; margin-left: auto; }
#bodycenter #dv1 { float: left;width: 280px;}
#bodycenter #dv2 { float: right; width: 410px;}
#footer{ width: 700px; margin-right: auto; margin-left: auto; overflow: auto; }  

单行三列
绝对定位

#left { position: absolute; top: 0px; left: 0px; width: 120px; }
#middle {margin: 20px 190px 20px 190px; }
#right {position: absolute;top: 0px; right: 0px; width: 120px;}  

float定位一
xhtml:

<div id="warp">
<div id="column">
<div id="column1">这里是第一列</div>
<div id="column2">这里是第二列</div>
<div class="clear"></div>
</div>
<div id="column3">这里是第三列</div>
<div class="clear"></div>
</div>

CSS:

#wrap{ width:100%; height:auto;}
#column{ float:left; width:60%;}
#column1{ float:left; width:30%;}
#column2{ float:right; width:30%;}
#column3{ float:right; width:40%;}
.clear{ clear:both;}

float定位二
xhtml:

<div id="center" class="column">
<h1>This is the main content.</h1>
</div>
<div id="left" class="column">
<h2>This is the left sidebar.</h2>
</div>
<div id="right" class="column">
<h2>This is the right sidebar.</h2>
</div>

CSS:

body {margin: 0;padding-left: 200px;padding-right: 190px;min-width: 240px;}
.column {position: relative;float: left;}
#center {width: 100%;}
#left {width: 180px; right: 240px;margin-left: -100%;}
#right {width: 130px;margin-right: -100%;}

两行三列
xhtml:

<div id="header">这里是顶行</div>
<div id="warp">
<div id="column">
<div id="column1">这里是第一列</div>
<div id="column2">这里是第二列</div>
<div class="clear"></div>
</div>
<div id="column3">这里是第三列</div>
<div class="clear"></div>
</div>

CSS:

#header{width:100%; height:auto;}
#wrap{ width:100%; height:auto;}
#column{ float:left; width:60%;}
#column1{ float:left; width:30%;}
#column2{ float:right; width:30%;}
#column3{ float:right; width:40%;}
.clear{ clear:both;}

三行三列
xhtml:

<div id="header">这里是顶行</div>
<div id="warp">
<div id="column">
<div id="column1">这里是第一列</div>
<div id="column2">这里是第二列</div>
<div class="clear"></div>
</div>
<div id="column3">这里是第三列</div>
<div class="clear"></div>
</div>
<div id="footer">这里是底部一行</div>

CSS:

#header{width:100%; height:auto;}
#wrap{ width:100%; height:auto;}
#column{ float:left; width:60%;}
#column1{ float:left; width:30%;}
#column2{ float:right; width:30%;}
#column3{ float:right; width:40%;}
.clear{ clear:both;}
#footer{width:100%; height:auto;}

PS:这里列出的是常用的例子，而非研究之用，对一每个盒子，都没有设置margin,padding,boeder等属