how to show a second dropdown based on previous dropdown selection and show third dropdown based on second dropdown ?

Question

then i want to click button for show total results. but i dont know.
https://code.sololearn.com/Wq4hXBA4PRNp/?ref=app

Answer 1

Hello M E(biologist)
See this link. I hope useful for you.
https://stackoverflow.com/questions/6954556/show-a-second-dropdown-based-on-previous-dropdown-selection
[UPDATE] :
Second link:
https://css-tricks.com/dynamic-dropdowns/
Goodluck 😉

Answer 2

hi Mohammad Yahya.thanks for your suggestion especially second link.🙏