Web实现点击图片弹出上传文件窗口

<style>
.fileInputContainer{
height:256px;
background:url(upfile.png);
position:relative;
width: 256px;
}
.fileInput{
height:256px;
overflow: hidden;
font-size: 300px;
position:absolute;
right:0;
top:0;
opacity: 0;
filter:alpha(opacity=0);
cursor:pointer;
}
</style>

<div class="fileInputContainer">
<input class="fileInput" type="file" name="" id="" />
</div>