how to pass a value from a list box to a php function

vasilis

I have a page with a form which contains a select box which gets populated from a mysql table through a php function when the page runs. I have added a 2nd list box above the previous one with hard-coded option values (it is located in the same form).
What I want to do is the following: When selecting a value in the hard-coded list box, this value should pass to the function that populates the other list box, i.e. this function should re-run but with the passed value from the hard-coded list box. (The reason I want to do this is that later I will modify the function so that it retrieves a subset of the previously retrieved group of values, i.e. values that
are related to the selected value in the hard-coded list box, in other words do a filtering in the previous group of values based on the selected value in the hard-coded list box).
I don't want the form to be submitted with the onChange event on the hard-coded list box because the action of the form refers to a script that I don't want to run when selecting a value in the hard-coded list box, I just want the page to refresh with the filtered values output in the list box below.

I hope I made myself clear. Appreciate any help.

djjjozsi

if you hardcode a listbox, is it short?

In the mysql table how many elements you have?

If that value is not a huge one, you can solve it with JS only to filter the 2th listbox.

If its a big selectbox, then a XMLHttpRequest() between a server side program can populate the 2th select box with an onChange event.

You can get ideas from here:
http://php-ajax-code.blogspot.com/2007/07/ajax-triple-dropdown-with-states-cities.html

vasilis

the list box will have only 6-7 hard-coded values (say box A). The thing is that I want the same php function to continue populating the previously existed list box (say box 😎 because it is a part of the code an e-commerce cart, so when the user selects a value in the B list box, the cart outputs a specific product's details to the user (as it has done before). Therefore, the filtered values that I want to output in the B list have to come from the same function internally so when selected, the cart will continue working as it used to work before (i.e. output a product's details). The only difference is that list box B will output filtered values based on the selected value in list box A.

djjjozsi

you can make an AJAX call to get the first hardcoded dropdown, and set an onChange event to start another javascript to get the related values.

on the linked (triple dropdown) tutorial you can chenge the "first dropdown"'s code.

I suggest that you should build an array to store the values for the first dropdown.

djjjozsi

if you want to edit a listbox, and populate a new one, you can design that here:

http://phpcode.hu/teszt/ajax/

this site makes then an updater code, which gives you a basic idea how to fill the existing data into a ~'div'
i suggest don't hardcode the first dropdown, that destroys the dynamism of your program.

This generator can built your table structure, so its helpful if you write such a program from the very beginning.