HELP - multiple select from database

kpowning

I have a script that is displaying the contents from my database that shows all the categories available for someone to select. What I'm looking to have done is that if the user selects on (category select list #1) then in the following (category select list #2) it will not show the same category listed there for the user to select again. I hope this makes sense. I appreciate any help on this.

I have seen this in javascript before, but is there a way to check this in .php and a sample would be much appreciated?

If it has to be java - does anyone have a sample for me to look at?

kpowning

Please ANYONE... this is almost the last part I need to figure out.

Basically two select boxes with the same categories for example:

Cars
Trucks
RV

Motorcycle

If someone selects cars in the first select field then in the second one I dont want cars to be listed as an option.

Trucks
RV