JSFiddle - React, Tailwind, and code Playground

HTML

<div id="custom_div" class="custom_div">This div will be highlighted</div>
<a href="#" id="custom_Link">Click to highlight the custom div in Child.html</a>

CSS

.custom_div {
    border: 2px solid #000;
    width: 200px;
    height: 200px;
    background: #0f0;
}

.highlight {
    background: #f00;
}

JavaScript

$('#custom_Link').hover(function () {
        $('#custom_div').toggleClass('highlight'); 
    });

    $('#custom_Link').click(function (e) {
       $('#custom_div').addClass('highlight');
        e.preventDefault();

    });