php - Combobox items based on selected item in another combobox

Question

If I have a combobox1 has the items: Fruits & vegetables.

I need to show a nother combobox2 based on the selected item in combobox1.

If the selected item in combobox1 is Fruits, then combobox2 items are: apple, orange ..etc.

If the selected item in combobox1 is vegetables, then combobox2 items are: radish, lettuce..etc.

How can I do that using PHP & HTML? (Please consider "PHP & HTML only" as a condition).

Answer 1

Unfortunately your conditions (PHP & HTML only, not javascript) means you should reload the page/load another page with a form submission after every change on your combobox, as it would be the only way for you to understand what is the selected value since you decided to work only server-side (PHP).

If you decide not to take advantage of javascript (or a javascript framework such as jQuery) you won't be able to modify contents in your page without form submission, therefore you won't be able to change the second combobox elements if you didn't submitted the first combobox selection.