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

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

#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;}

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

#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:20px190px20px190px;}
#right{position:absolute;top:0px;right:0px;width:120px;}
float定位一
xhtml:

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

<divid="center"class="column">
<h1>Thisisthemaincontent.</h1>
</div>
<divid="left"class="column">
<h2>Thisistheleftsidebar.</h2>
</div>
<divid="right"class="column">
<h2>Thisistherightsidebar.</h2>
</div>
CSS:

.column{position:relative;float:left;}
#center{width:100%;}
#left{width:180px;right:240px;margin-left:-100%;}
#right{width:130px;margin-right:-100%;}

xhtml:

<divid="warp">
<divid="column">
<divid="column1">这里是第一列</div>
<divid="column2">这里是第二列</div>
<divclass="clear"></div>
</div>
<divid="column3">这里是第三列</div>
<divclass="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;}

xhtml:

<divid="warp">
<divid="column">
<divid="column1">这里是第一列</div>
<divid="column2">这里是第二列</div>
<divclass="clear"></div>
</div>
<divid="column3">这里是第三列</div>
<divclass="clear"></div>
</div>
<divid="footer">这里是底部一行</div>
CSS: