JSFiddle - React, Tailwind, and code Playground

HTML

<div id="topjob-contain">
    <img src="https://commons.wikimedia.org/wiki/File:Foo.jpg">
    
    <div class="newjobz">
        <h1><a href="#" target="_blank">#1 Random Job Title Here</a></h1>
        <p>#1 Random Agency Name here</p>
        <p>#1 Random Discription of job : .sed diam nonumm tincidunt ut laoreet dolorey nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. </p>
        <br clear="all" />
    </div>
    
    <div class="newjobz">
        <h1><a href="#" target="_blank">#2 Random Job Title Here</a></h1>
        <p>#2 Random Agency Name here</p>
        <p>#2 Random Discription of job : .sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. </p>
        <br clear="all" />
    </div>
    
    <div class="newjobz">
        <h1><a href="#" target="_blank">#4 Job Title Here</a></h1>
        <p>#3 Random Agency Name here</p>
        <p>#3 Random Discription of job : .sed diam nonummy t ut laoreet dolore magna aliquam erat volutpat. </p>
        <br clear="all" />
    </div>
    
    <br clear="all" />
</div>

CSS

.newjobz{ display: none; }

JavaScript

function randomFromTo(from, to) {
    return Math.floor(Math.random() * (to - from + 1) + from);
}

function displayRandomJob() {
    var r = randomFromTo(1, $('div.newjobz').length);
    $('div.newjobz').hide().eq(r - 1).show();
}

$(document).ready(function() {
    displayRandomJob();
    $('#jobchanger').click(function() {
        displayRandomJob();
    });
});