How to make smooth animation in js?

Question

JavaScript

There is a table in a table. (spoiler alert) and her first outing is very rough. It just appears, although the animation works fine after that. How can I make the first "animation" when entering the site and clicking it also be smooth?

Here is an example of my code.
jsfiddle.net/ny0ht7cd/52

Answer 1

.spoiler_block div {
  display: none;
}

$('.spoiler_title').click(function() {
  $('.spoiler_block div').slideToggle(250);
});