How to expand and collapse a div based on timing?

Question

css

Good afternoon!
The site on flexbox, in the mobile version (to save space) the lower part of the div is hidden through overflow hidden, expands and collapses by the button. Is it possible to implement opening and hiding by timing?

Those. the user opened the site, immediately with him the block opened and closed in half a second, the demonstration took place, then, if he wants, he will open it by the button.
Can you please tell me if this is possible and by what means?

Answer 1

https://learn.javascript.ru/settimeout-setinterval