JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.js"></script>
<span class="basket_amount">65.70</span>

JavaScript

function versandkosten() {
	console.log('called versandkosten');
}
$(document).ready(function() {
var observer = new MutationObserver(function(e) {versandkosten();});
var $basketAmount = $('.basket_amount');
observer.observe($($basketAmount)[0], {characterData: true, childList: true});
	// test changing the content of the element
  $basketAmount[0].innerHTML = 77;
  
  // changing it via jQuery would call it twice!
  // $basketAmount.html(77);
});