使得select选择框也可以输入

<script language="javascript"> 
    function changeF()  
    {  
       document.getElementById('makeupCo').value=  
       document.getElementById('makeupCoSe').options[document.getElementById('makeupCoSe').selectedIndex].value;  
    }  
</script> 
 
<span style="position:absolute;border:1pt solid #c1c1c1;overflow:hidden;width:188px;  
    height:19px;clip:rect(-1px 190px 190px 170px);"> 
<select name="makeupCoSe" id="makeupCoSe" style="width:190px;height:20px;margin:-2px;" onChange="changeF();"> 
    <option id='1' value='java'>java</option> 
    <option id='2' value='c++'>c++</option> 
    <option id='3' value='python'>python</option> 
    <OPTION id="99999" VALUE="" SELECTED> 
</select> 
</span> 
<span style="position:absolute;border-top:1pt solid #c1c1c1;border-left:1pt   
    solid #c1c1c1;border-bottom:1pt solid #c1c1c1;width:170px;height:19px;"> 
    <input type="text" name="makeupCo" id="makeupCo" value="请选择或输入" style="width:170px;height:15px;border:0pt;"> 
</span>