body { margin: 0px; padding: 0px; text-align: center; } 

#content { margin-left:auto; margin-right:auto; width: 400px; width: 370px; }

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;}

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; }

#bodycenter { width: 700px;margin-right: auto; margin-left: auto;overflow: auto; } 

#bodycenter #dv1 {float: left;width: 280px;} 

#bodycenter #dv2 {float: right;width: 410px;}

#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;}

#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; }

#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:

以下是引用片段：

<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>

#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;}

<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>

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%;}

<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>

#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;}

<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>

以下是引用片段：

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等属性！