JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#" id="test">test test</a>
<div id="siren">wahhh!</div>

CSS

#siren {
    color: white;
    background: red;
    display: none;
}

JavaScript

var marker;
$('#test').on('mouseover', function() {
    marker = setInterval(function() {
        $('#siren').show().fadeOut('slow');
    }, 500);
}).on('mouseout', function() {
    clearInterval(marker);
});