How to set animation time in JS?

Question

css

Help me please. I started making a website, but js came in handy (I don’t know it at all) and I don’t know how to make an animation when opening a link so that it opens at a given time

https://jsfiddle.net/ufhkd9xt/1/

here is my code

Answer 1

https://jsfiddle.net/Ravshanbek778/ychqvptg/
There is such a crooked way (but it's not good)
In general, you need to use animationkeyframes (or you can use setTimeout) if you want to use pureJS
And if there is a possibility of jquery, then there is already built-in
https:/ /api.jquery.com/show/#show
https://api.jquery.com/hide/#hide