Dropdown menu updates after clicking one?

[iBuddy]

I have seen this on lot of sites, where say you goto a car site, and you click the make of the car from a drop down menu, and than after u click it, it will load up the appropriate models for that make. How do I set this up pullin from php and mysql?

Im guessing I would have have to do some sort of javascript onclick function?

[leatherback]

Hi,

A number of options:

Most safe to work, no javascript:
Have the user submit the car-make by hand, then select from the database the models matching that make, and load that droplist in the page

AJAX-driven:
Use AJAX to query the database after each choice was made (Never having used AJAX, I am not sure how to do it in detail)

Javascript-submitted:
Use javascript to submit the form using the onChange() function in the dropdown menu. Handle as in option 1.

Fully javascript driven:
Load all makes, models from the datbase, and echo them into javascript arrays on your page. Use javascript to build the dropdown after each selection is made using the onchange() function.

Downside with all javascript-driven forms is that they require the user to have javascript switched on.
Downside with all submitted forms is the need to reload the full page.
Downside with loading all the variables is the potentially enormous overhead to load all options.

Take your preferred pick.

[iBuddy]

Anyone know any tutorials or anything I can read about this?