JSFiddle - React, Tailwind, and code Playground

HTML

<div id="marketingProd">
  <select class="marketingProd" name="marketingProd[]" id="marketingprod1">
    <option value=""></option>
    <option value="1">One</option>
    <option value="2">Two</option>
    <option value="3">Three</option>
    <option value="4">Four</option>
    <option value="5">Five</option>
  </select>
  <div class="newProd" id="newProd2">
    <select class="marketingProd" name="marketingProd[]" id="marketingProd2">
      <option value=""></option>
      <option value="1">One</option>
      <option value="2">Two</option>
      <option value="3">Three</option>
      <option value="4">Four</option>
      <option value="5">Five</option>
    </select>
  </div>
  <div class="newProd" id="newProd3">
    <select class="marketingProd" name="marketingProd[]" id="marketingProd3">
      <option value=""></option>
      <option value="1">One</option>
      <option value="2">Two</option>
      <option value="3">Three</option>
      <option value="4">Four</option>
      <option value="5">Five</option>
    </select>
  </div>
</div>

JavaScript

$(document).ready(function() {
  $("#marketingProd").on("change", "select", function() { // delegated to the SELECT
    $("#marketingProd select").each(function() {
        alert($(this).val()); // Fixed syntax error here
    });
   });
});