多个div在一行

<style type="text/css">
<!--

.all {background: #F00;width:100%;height:100px;text-align:center;}
.main {width:200px;margin:0 auto} /*这里width:200px是里面div的宽度总和*/
.main1,.main2,.main3,.main4 {float:left}
.main1{background:#000;width:50px;height:100px}
.main2{background:#FF0;width:50px;height:100px}
.main3{background:#00F;width:50px;height:100px}
.main4{background:#F0F;width:50px;height:100px}
-->
</style>

<div class="all">
<div class="main">
<div class="main1"></div>
<div class="main2"></div>
<div class="main3"></div>
<div class="main4"></div>
</div>
</div>