css 实现蒙版效果

样式：

<style> .back {background:url(images/coupon-logo.gif) no-repeat;} .top {height:100px;background-color:#fff;filter:Alpha(Opacity=60);opacity:0.6;} </style>

html

<div class="back">
    <div class="top"></div>
</div>

关键代码
background-color:#fff;filter:Alpha(Opacity=60);opacity:0.6;