<!DOCTYPE html>
<head>
<meta charset="utf-8"/>
<style type="text/css">
body{margin:0;padding:0;}
.div_content{
background: url("1.gif") no-repeat;
/*给input框添加背景图片，以凸显其透明效果。*/
width: 200px;
height: 200px;
}
.div_content>input{
outline: none;
border: none;
background-color: transparent;
/*必须将背景色设为透明，否则无效。（除非对于要设置的元素本身已经是透明的，如：span元素等）*/
background-color: rgba(0,0,0,0.25);
filter: progid:DXImageTransform.Microsoft.Gradient(startColorstr=#40000000,endColorstr=#40000000);
}
</style>
</head>
<body>
<div class="div_content">
<input type="text" size="20"/>
</div>
</body>
</html>
