JSFiddle - React, Tailwind, and code Playground

HTML

<div id="movies">
    test
</div>

CSS

#movies {
    opacity: 0;
}

JavaScript

var movies = document.getElementById("movies");
var opacity = 0.1;
    var apparence = function(){
        if(opacity <= 1.0) {
            movies.style.opacity =  opacity;
        } else { 
            clearInterval(timer);
        }
        opacity += 0.1;
    }

    var timer = window.setInterval(apparence, 1000);