Javascript下拉选定的值在IE中不起作用

Question

我有一个javascript switch case语句来重定向页面或显示/隐藏文本框取决于用户从下拉框中选择的值。它在Firefox中正常工作，但不是IE。该错误消息是如下： SCRIPT5007：无法获得属性“值”的值：对象为空或未定义 _index.htm 67行字符7

开关（document.form.description.options [描述.selectedIndex] .value） - IE浏览器在form.desciprition上遇到困难。

<script language="javascript"> 
function fundsource() 
    { 
     var val; 


     for (i=0; i< document.form.description.length; i++) 
     { 

      switch (document.form.description.options[description.selectedIndex].value) 

      { 
       case "Select": 
        document.form.scholarship.style.visibility='hidden'; 
        document.form.description_other.style.visibility='hidden'; 
        break; 
       case "Wall of Friends": 
        location.href= some url 
        break; 
       case "Scholarship": 
        document.form.scholarship.style.visibility='visible'; 


        break; 
       case "Other": 
        document.form.description_other.style.visibility='visible'; 
        document.getElementById("descriptionspan").style.visibility="visible"; 
        break; 


      } 
     } 
    } 
</script> 

HTML如下代码：

<tr> 
        <td align="right">Description of the Fund for Your Donation <br /></td> 
        <td> 

     <select name="description" id="description" onchange="fundsource()"> 
         <option>Select</option> 
         <option>Scholarship</option> 
         <option>Rainbow of Life</option> 
         <option>Wall of Friends</option> 
         <option>General</option> 
         <option>Other</option> 

        </select> 
        <select name="scholarship" id="scholarship" style="visibility:hidden;"> 
         <option>Alumni Scholarship</option> 
         <option>Other</option> 
        </select> 
        </td> 
        </tr> 
        <tr> 
        <td align="right" valign="top"><div id="descriptionspan" alt="description" style="visibility:hidden;">Other, please specify:</div></td> 
        <td><input type="text" name="description_other" size="50" alt="Fund Other" style="visibility:hidden;" /></td> 
        </tr> 

我改变了document.form.description.options [description.selectedIndex]。价值到document.form.description.options [description.selectedIndex]。文字，它仍然不起作用。请指教。 TIA。