我下将下图左边的"所有用户"提取到右边去,我左边的所以用户提取的方式是
<td valign="top" align="left" width="49%" bgcolor="#C8DFFE">
        <p align="center">所有用户:</p>
          <p align="center"> 
                   <select name="allUser" size="12" multiple ID="Select1">
                                        <%
                                        sql="select yhm from user "
                                                 '----------------
                                         response.write(sql)
                    searchtable my,sql,rs ''查询数据库
                    if not rs.eof then ''如果有这个调查记录
                         for i=1 to rs.recordcount
                          Response.Write("<option value="+rs("yhm")+">"+rs("yhm")+"</option>")
                                                  yhm=rs("yhm")
                          rs.MoveNext
                        next
                       closetable rs
                        end if
                                
                                %>
                                </select>        
                        </td>
请教我右边的用户只能从左边选择应该怎么写