JSFiddle - React, Tailwind, and code Playground

HTML

<p class="dopln">TEST1</p>
<p class="dopln">TEST2</p>
<p class="dopln">TEST3</p>

JavaScript

var elementy = $(".dopln");
for (var i = 0; i < elementy.length; i++) {
	elementy[i].innerText += " - DOPLNÄšNO"
}