JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <input id="newcarousel" type="button" value="Добавить карусель">
    </input>
</body>

JavaScript

document.querySelector("input").addEventListener("click", Init, false);
function Init()
{		
        alert("!!");
        var div = document.createElement("div");
		document.querySelector("body").appendChild(div);
		document.querySelector("body div:last-child").classList.add("carousel");
   
        alert(document.querySelector("body").innerHTML);
}