JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <p class="special">Special 0</p>
</div>
<input type="button" value=" add special "/>

JavaScript

$(':button').click(function(){
    $('<p>', {text: 'New special ' + $('.special').length, class: 'special'}).appendTo('div');
});

document.addEventListener('DOMNodeInserted', function(e){
    alert($('.special').length);
});