JSFiddle - React, Tailwind, and code Playground

HTML

<div id="hiddenSecrets">
    <p id="valueOne"></p>
    <p id="valueTwo"></p>
</div>

CSS

#hiddenSecrets {
    display: none;
}

#valueOne:after {
    content: "2048";
}

JavaScript

var div = $('#hiddenSecrets');
div.show().css({'opacity': '0'});
var str = window.getComputedStyle($('#valueOne')[0], ':after')
                .getPropertyValue('content');
div.css({'opacity': '1'}).hide();
alert(str);