In order to create a Dynamic Drop-down change form with RSForm! Pro you will have to add two drop-down fields to your form and also use a script similar to the following one in order to adjust the fields dynamically: <script type="text/javascript"> function dynamic1(parent,child){ var parent_array = new Array(); parent_array[''] = ['Please select a manufacturer']; parent_array['Audi'] = ['A3','A4','A5','A6','A8','Q5','Q7','S3','S4','S5','S6','S8','RS6']; parent_array['Dacia'] = ['Sandero','Logan']; parent_array['FIAT'] = ['Bravo','Punto','Grande Punto']; parent_array['Peugeot'] = ['207','308','407','607']; parent_array['SEAT'] = ['Ibiza','New Ibiza','Leon']; parent_array['Skoda'] = ['Fabia','Octavia Tour','Octavia 2','Superb']; var thechild = document.