select消除边框 border: medium none;

    <select>  
      <optgroup label="Swedish Cars">  
        <option value="1">Volvo</option>  
        <option value="2">Saab</option>  
      </optgroup>  
      <optgroup label="German Cars">  
        <option value="3">Mercedes</option>  
        <option value="4">Audi</option>  
      </optgroup>  
    </select>  

把宽设置短一点，就看不到文本框
<input type="file" style="width: 73px;">

select消除边框  border: medium none;