JSFiddle - React, Tailwind, and code Playground

HTML

<img class="clearCircle" id="greenCircle" src="http://placehold.it/200x200/66ff66" alt="Clear circle">
<img class="clearCircle" id="blackCircle" src="http://placehold.it/200x200/000000" alt="Clear circle">

CSS

.clearCircle {
    position: absolute;
    height: 50;
    width: 50;
}

JavaScript

$(function () {
    var lockTime = 2000;
    var greenCircle = "#greenCircle";
    var blackCircle = "#blackCircle";

    $(greenCircle).css("z-index", "20");
    $(blackCircle).css("z-index", "10");
    $(greenCircle).animate({
        width: '50%',
        height: '50%',
        left: '-50%',
        top: 0
    }, lockTime);
});