without a button, you will have to do it with javascript.
the simplest thing is to add an onChange event to your select
element
which will relocate the user to the next page, passing
selected value as
url variable:
<select name="myselect"
onChange="window.location.href='nextpage.cfm?cat='+this.value;">
the above will take the user to nextpage.cfm?cat=[value of
selected
option]. so on the nextpage.cfm query your db to get the
subcategories
that belong to #url.cat# category.
there are other, more complicated ways to do it: you may want
to google
"two selects related", which will show you how to populate a
second
select element on the same page based on selection in the
first select
element.
hth
Azadi Saryev
Sabai-dee.com
http://www.sabai-dee.com/