JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#" id="button">DODAJ</a>
<div id="boxes"></div>

CSS

#button{
    padding:5px 20px;
    background:blue;
    color:#fff;
}

.square{
    width:30px;
    height:30px;
    margin:10px;
    background:red;
    float:left;
}

JavaScript

$( "#button" ).click(function() {
  $('#boxes').append('<div class="square"></div>');
});