ASP.NET上传图片时，产生预览

<tr bgcolor=#f5f5f5>      <td height=30 align=center valign=middle>图片链接</td>      <td height=35 align=center valign=middle><input type=file name=uploadfile1 runat=server id=uploadfile1 onpropertychange=document.all.imgID.src=file:///+this.value> &nbsp;      </td>     </tr>     <tr bgcolor=#f5f5f5>      <td height=70 align=center valign=middle>缩略图</td>      <td height=70 align=center valign=middle><img id=imgID width=82 height=65 border=0 >&nbsp;      </td>     </tr>