<script language=vbscript>
sub city_onchange
if form.city.value="北京" then
form.action="beijing.asp"
elseif form.city.value="上海" then
form.action="shanghai.asp"
elseif form.city.value="天津" then
form.action="tianji.asp"
elseif form.city.value="" then
msgbox "请选择一个选项"
end if
form.submit