请问如何实现选择下拉菜单，另一文本框为不可编辑

[hengsf2008]

<%
j = 1

set rs=createobject("adodb.recordset")
set rs.activeConnection=conn
if session("right") = 2 then
' str ="select user1,flag,dept from V_users where dept<>'派驻机构' "
str ="select user1,flag,dept from V_users "
else
str ="select * from tb_user where dept='"&dept&"'"&"order by id "
end if
set rs=conn.execute(str)
do while not rs.Eof
var = "A"&j
var2 = "SD"&j //开始时间
var4 = "ED"&j //结束时间
var5 = "T"&j //时间段
var6 = "R"&j
var7 = "DP"&j
%>
<tr>
<td height="20" align="center"><%=rs("user1")%></td>
<% if session("right") = 2 then %>
<td align="center"><%=trim(rs("dept"))%></td>
<% end if %>
<td align="center"><input type="hidden" name=<%=var7%> value="<%=trim(rs("dept"))%>">
<select name=<%=var%> size="1">
<option value="0">无</option>
<option value="1">在岗</option>
<option value="2">本市出差</option>
<option value="3">市外出差</option>
<option value="4">迟到</option>
<option value="5">早退</option>
<option value="6">旷工</option>
<option value="7">补休</option>
<option value="8">公休假</option>
<option value="9">事假</option>
<option value="10">病假</option>
</select>
</td>
<td align="center"><input name=<%=var2%> type="text" value="<%=getdate%>" size="10" maxlength="10"></td>
<td align="center"><input name=<%=var4%> type="text" value="<%=getdate%>" size="10" maxlength="10"></td>
<td align="center">
<select name=<%=var5%> size="1">
<option value="0" selected>上午</option>
<option value="1">下午</option>
<option value="2">全天</option>
</select></td>
<td align="center"><input name=<%=var6%> type="text" size="16"></td>
</tr>
<%
j = j + 1
rs.movenext
loop
person = j - 1
rs.close
set rs=nothing
%>


即当选择“在岗”时，“开始时间”、“结束时间”和“时间段”均为不可编辑状态。因没有接触过VB，请大神写完整代码，谢谢！