JSFiddle - React, Tailwind, and code Playground

HTML

<span class='ui-bar ui-overlay-c ui-corner-all' ><img width='50px' height='50px' src='http://www.shougun.it/images/loading.gif' /><br><h2>Chargement en cours...</h2></span>

CSS

.ui-bar{
    display:none;
position:absolute;
    top:0;
    left:0;
    height:100%;
    width:100%;
    background-color:rgba(255,0,0,.5);
    text-align:center;
    
}
.ui-bar img {
    height:50px;width:50px;
    margin:auto;
}

JavaScript

setTimeout(function(){
$(".ui-bar").css("display","block");

    },2000);