JSFiddle - React, Tailwind, and code Playground
HTML
<button class="mybtn">Show</button>
<div class="foo">BAR</div>
----
CSS
.foo {
opacity: 0;
transition: all 400ms;
}
.foo.active {
opacity: 1
}
JavaScript
$('.mybtn').click(function() { $('.foo').toggleClass('active'); })