JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.1.1/css/bootstrap.min.css">
<div class="alert alert-danger hide-me" name="alert-message" id="alert-message">Formato não permitido !</div>

<button id="testBtn"> Simulate wrong file choice </button>

CSS

.hide-me{
        display: none;
}

JavaScript

$('#testBtn').click(function(){
$(".alert").show();
  window.setTimeout(function() {
    $(".alert").fadeTo(1500, 0).slideUp(500, function(){
        $(this).css({'opacity': 1});
   });
}, 10000);
});