Question about hiding <div> elements

Question

Hi guys!
How can I make it possible to open only one "id" element at a time?
For example: I open <div id = "a1"> Then I open <div id = "b1"> at this point <div id = "a1"> must be closed automatically. How to do this?
Thank you.
https://code.sololearn.com/WPfC7s5iV45i/?ref=app

Answer 1

Some ways:

https://code.sololearn.com/WN8Yrr1XU9v6/?ref=app

https://code.sololearn.com/WOp2LwlbaUzs/?ref=app

Answer 2

You're very welcome. 🙂

Answer 3

Janning, Thank you so much;)

Answer 4

Another way to do this. Explanations in Russian, but the code in English, of course:
https://webcareer.ru/pereklyuchatel-vkladok-na-jquery.html#comment-613