JSFiddle - React, Tailwind, and code Playground

HTML

<div id="clock">12:00PM</div>

CSS

.hidden {
    visibility:hidden;
}

div {
    font-size:30px;
    font-weight:bold;
    font-family:'courier new'
}

JavaScript

$clock = $("#clock");
$blink = true;
setInterval(function(){
    if ($blink) {
        $clock.html($clock.html().replace(":",'<span class="hidden">:</span>'));
        $blink = false;
    }
    else {
        $clock.html($clock.html().replace('<span class="hidden">:</span>',":"));
        $blink = true;
    }
}, 1000);