Linking categor&manufacts dropdownlists

[Golferas]

I recently downloaded Oscommerce 2.2 besides contribution 46, Category Drop Down List. The think is I've got now in my web two onchange drop down lists, categories and manufacturers, none a subcategory of the other.

 

I want to make 'em work together: p.e: if I select categories - salads, I want to see all salads, but, if afterwards I select manufacturers - mcdonals, I just wanna see from the afore selected salads, only the MCD ones. If again I select, p.e, categories - blank default, then display all MCDs products whichever they are.

 

Does somebody know how to work this out??? I don't want Dropdownmenu v2.6 nor any click a button solution, just this two onchange dropdowns working together.

 

Whoever helps, thank you sooooooooooo much!!!