两栏布局，左边宽度固定，右边自适应

<div id="left">left</div>

<div id="right">right</div>

<style>

#left{

width: 200px;

line-height:50px;

background:green;

float:left;

text-align:center;

}

#right{

margin-left:200px;

line-height:50px;

background:red;

text-align:center;

}

</style>