前端：input样式

<a href="javascript:;" class="a-upload">
    <input type="file" name="" id="">点击这里上传文件
</a>

<a href="javascript:;" class="file">选择文件
    <input type="file" name="" id="">
</a>

/*a  upload */
.a-upload {
    padding: 4px 10px;
    height: 20px;
    line-height: 20px;
    position: relative;
    cursor: pointer;
    color: #888;
    background: #fafafa;
    border: 1px solid #ddd;
    border-radius: 4px;
    overflow: hidden;
    display: inline-block;
    *display: inline;
    *zoom: 1
}

.a-upload  input {
    position: absolute;
    font-size: 100px;
    right: 0;
    top: 0;
    opacity: 0;
    filter: alpha(opacity=0);
    cursor: pointer
}

.a-upload:hover {
    color: #444;
    background: #eee;
    border-color: #ccc;
    text-decoration: none
}

/*file */
.file {
    position: relative;
    display: inline-block;
    background: #D0EEFF;
    border: 1px solid #99D3F5;
    border-radius: 4px;
    padding: 4px 12px;
    overflow: hidden;
    color: #1E88C7;
    text-decoration: none;
    text-indent: 0;
    line-height: 20px;
}
.file input {
    position: absolute;
    font-size: 100px;
    right: 0;
    top: 0;
    opacity: 0;
}
.file:hover {
    background: #AADFFD;
    border-color: #78C3F3;
    color: #004974;
    text-decoration: none;
}

 

 <div class="file-box"> 
    <form id="uploadForm"> 
        <input type="text" id="textfield" class="txt" />
        <input type="button" class="btn" value="浏览..." /> 
        <input type="file" name="file" class="file" id="fileField" onchange="document.getElementById('textfield').value=this.files[0].name"/> 
        <input type="submit" class="btn" value="上传" /> 
    </form> 
</div>