ul列表，点击出现下拉菜单
ul列表，点击出现下拉菜单我要实现的是 鼠标点击li标签，出现它的下级菜单
请问怎么实现？
<%
set rs=Server.CreateObject("ADODB.Recordset")
sql="select * from [BigClass] order by BigClassId asc"
rs.open sql,conn,1,1
%>
<ul class="about" >
<%
if not rs.eof then
i=1
do while not rs.eof
%>
<li id="imgmenu<%=i%>" onClick="showsubmenu(<%=i%>)" style="cursor:hand;"><%=rs("BigClassName")%>
<ul id="submenu<%=i%>" style="DISPLAY: none">
<%
sql="select * from [SmallClass] where BigClassName='"&rs("BigclassName")&"' ORDER BY SmallClassID ASC"
set rss=server.CreateObject("adodb.recordset")
rss.open sql,conn,1,1
if rss.recordcount<>0 then
do while not rss.eof
%>
<li><a href="product_list.asp?SmallClassName=<%=rs("SmallClassName")%>" class="aboutlist"><%=rss("SmallClassName")%></a></li>
<%
rss.movenext
loop
end if
rss.close
set rss = nothing
%>
</ul>
</li>
<%
rs.movenext
loop
end if
rs.close
set rs=nothing
%>
</ul>
