Write some Software

I require a software program written for my website which reveals the product/s available for a customer to buy based on the customer selecting their vehicles' make, model and year of manufacture from drop down boxes that only appear on the screen as a selection is made from the previous drop down box. The data in each new drop down box that appears is to be based on the selection made from the previous drop down box so only the matching details are shown, finally revealing the product that is suited to the vehicle make, model and year selected.