<style type="text/css">

.ie6-out{
       _margin-left:900px;
       _zoom:1;
}
.ie6-in{
       _position:relative;
       _float:left;
       _margin-left:-900px;
}
#min-width{
       min-width:900px;
       background:#ccc;
       line-height:200px;
       _zoom:1;
}
</style>

<div class="ie6-out">
  <div class="ie6-in">
    <div id="min-width">ie6-下，容器实现模拟min-width效果。请任意改变浏览器窗口大小，再点击按钮“查看宽度”。</div>
  </div>
</div>

<style type="text/css">
body{ text-align:center;}
#min-width{
       min-width:900px;
       _width:expression((document.documentElement.clientWidth||document.body.clientWidth)<900?"900px":"");
       line-height:200px;
       background:#ccc;
}
</style>
<div id="min-width">ie6-下，容器实现模拟min-width效果。请任意改变浏览器窗口大小，再点击按钮“查看宽度”。</div>