<select name="SelectedItem" id="SelectedItem" size=12 multiple="true">
<option>无</option>

</select>
</select>
</td>
<td width="60" align=center>
<br><br>
<button onClick="MoveSingleItem(WaitSelectItem, SelectedItem)">&lt;</button><br><br>
<button onClick="MoveAllItems(WaitSelectItem, SelectedItem)">&lt;&lt;</button><br><br><br><br>
<button onClick="MoveSingleItem(SelectedItem, WaitSelectItem)">&gt;</button><br><br>
<button onClick="MoveAllItems(SelectedItem, WaitSelectItem)">&gt;&gt;</button><br>
</td>
<td width="220" align=center valign="top">
待分配的栏目：<br><br>
<select name="WaitSelectItem" size=12 multiple=true>
<option>师大要闻</option>
<option>视频新闻</option>
<option>图片新闻</option>
<option>专题要闻</option>
<option>十万个为什么</option>
<option>代码测试</option>
<option>www.why100000.com</option>
</select>
</td>
</tr>
</table>
</form>

<script language="javascript">
function MoveSingleItem(sel_source, sel_dest)
{
if (sel_source.selectedIndex==-1) //源：没有点选任何项目
return;

if (sel_source.options[0].text=="无") //源：只有“无”项目
return;

if (sel_dest.options[0].text=="无") //目标：只有“无”项目，则先删除该提示性项目
sel_dest.options.remove(0);