JSFiddle - React, Tailwind, and code Playground

HTML

<div id="loader">
               <div id="loading-image"></div>
        </div>

CSS

#loader
{
    display:none;
    background-color: red;
    width:32px;
    height: 32px;
    position: fixed;
    text-align:center;
    z-index:9999;
    overflow: auto;
}
#loading-image {
  position: absolute;
  z-index: 99999;
}

JavaScript

var url = 'http://nomesito.it';

jQuery.ajax({
    url: url,
    type: 'POST',
    data: {id: post},
    success: function(data) {
        jQuery("#result").html(data);
    },
    beforeSend:function(){
        jQuery("#loading").show();
    },
    complete:function(){
        jQuery("#loading").hide();
    }
});