IE9 调试javascript SCRIPT5007: 属性“ShowLink”的值为 null、未定义或不是 Function 对象
SCRIPT5007: 属性“ShowLink”的值为 null、未定义或不是 Function 对象 
IE9 调试结果如下：
<script language="javascript" type="text/javascript">ShowLink('word');<


可是我的代码如下，请问哪儿有错啊？
aspx代码如下
———————————————————————————————————————————————————————
<%
   
  switch (i_NewsType)
  {
  case 0:
  ExecuteJs("ShowLink('word');");
  break;
   
  case 1:
  ExecuteJs("ShowLink('pic');");
  break;
  case 2:
  ExecuteJs("ShowLink('url');");
  break;  
  default:
  ExecuteJs("ShowLink('word');");
  break;
  }
%>

.cs的代码如下
——————————————————————————————————————————————_____

  protected void ExecuteJs(string sentence)
  {
  Context.Response.Write("<script language=\"javascript\" type=\"text/javascript\">");
  Context.Response.Write(sentence);
  Context.Response.Write("</script>");
  }

javascript代码如下
____________________________________________________________________________________________________________
function ShowLink(NewsType)
{
  switch (NewsType)
  {
  case "word":
document.getElementById('div_showad').style.display='';
document.getElementById('div_URLaddress').style.display='none';
document.getElementById('div_PicURL').style.display='none';
document.getElementById('div_Content').style.display='';
document.getElementById('div_Templet').style.display='';
document.getElementById('div_Souce').style.display='';
document.getElementById('NewsProperty_CommTF').style.display='';
document.getElementById('NewsProperty_DiscussTF').style.display='';
document.getElementById('NewsProperty_FILTTF').style.display='none';
  document.getElementById('isFiles_div').style.display ="";
  document.getElementById('isFiles_div1').style.display ="";
  document.getElementById('div_vURL').style.display = "";
break;
  case "pic":
document.getElementById('div_showad').style.display='';
document.getElementById('div_URLaddress').style.display='none';
document.getElementById('div_PicURL').style.display='';
document.getElementById('div_Content').style.display='';
document.getElementById('div_Templet').style.display='';
document.getElementById('div_Souce').style.display='';
document.getElementById('NewsProperty_CommTF').style.display='';
document.getElementById('NewsProperty_DiscussTF').style.display='';
document.getElementById('NewsProperty_FILTTF').style.display='';
  document.getElementById('isFiles_div').style.display ="";
  document.getElementById('isFiles_div1').style.display ="";
  document.getElementById('div_vURL').style.display = "";
break;
  default :
document.getElementById('div_showad').style.display='none';
document.getElementById('div_URLaddress').style.display='';
document.getElementById('div_PicURL').style.display='';
document.getElementById('div_Content').style.display='none';
document.getElementById('div_Templet').style.display='none';
document.getElement