建议就放两个复选框
<select ... name=selectname onchange="aaa()">
<select ... name=selectname onchange="aaa()">
<script>
sub aaa()
if theform.select.value="第一个选项的值" then
theform.a.name=xxx
theform.b.name=xxx
end if
.
.
.
end sub
</script>
刚开始时将a,b,,c,d,e,f设为disabled,
<select ... name=selectname onchange="aaa()">
<script>
sub aaa()
if theform.select.value="第一个选项的值" then
theform.a.disabled=false
theform.b.disabled=false
end if
.
.
.
end sub
</script>