JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container"></div>
 <div id="loading-img" style=" z-index: 20;display:none;"></div>
 <button id="button">Submit</button>

CSS

#loading-img {
	background: url(../images/loading-bar.gif) center center no-repeat;
}
.container{
    background: #e9e9e9;
}

JavaScript

$("#button").click(function() {
    $("#container").css("opacity",0.5);
   $("#loading-img").css({"display": "block"});
});