how make automatic generator for the search form

i have question about the automatic creation of the search form, compared to other scripts of classified ads that the creation of these search forms this automatically after the administrator of the website Flynax creates a category of ads customize for example the car catigorie her and in the vehicle catigorie!
- What does a search form compatible with the car category mean, which has already been customized on the ad addition form?
- if not how can it regenerate at the good reset search forms for what is the same with the elements of the ad add form?

finally how to create automatically a search form compatible with the same elements of the form to add the announcement of the same category


(search form) = (form to add)
thank you