<div class="fileUpload btn btn-primary">
<span>Upload</span>
<input type="file" class="upload" />
</div>
.fileUpload {
position: relative;
overflow: hidden;
margin: 10px;
}
.fileUpload input.upload {
position: absolute;
top: 0;
right: 0;
margin: 0;
padding: 0;
font-size: 20px;
cursor: pointer;
opacity: 0;
filter: alpha(opacity=0);
}
