I have tried to investigate the best approach to implementing drop down lists, but am still not sure how best to do it in the following situation. Can anyone point me to some relevant examples or tutorials?

I have a horizontal list of options (read from a Mysql database) which are displayed in a thin horizontal frame within a frameset. For each item on the list there may be between zero and, say, 10 sub options, again from the database. The user must be able to select at the sub-option level in order to display specific information in the other frames within the frameset. I already have the code for selecting at the option level but now need to do it at the sub-option level instead.

So, I would now like to have a neat drop down list of sub-options when they click a main option (or possibly hover over it), and then refresh the other frames when they click a sub-option from the drop down list.

I have seen that this can be done using forms, but that looks a bit clunky, and I don't want the little arrow. I have also seen some Javascript examples but I'm not sure how to do this or whether it would work when my horizontal frame is very thin - the list would have to drop down over the frame below - can it do that?

I have also seen a solution using Layers - is that what I need to do?

Any suggestions will be gratefully received.