JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>

<div class="content-section">
  <form method="POST">
    {% csrf_token %}
    <fieldset class="form-group">
      <div id="event_name">
        {{ form.event_name|as_crispy_field }}
      </div>
      <div id="recurring_event">
        <select id="id_recurring_event">
          <option value="Yes">Yes</option>
          <option value="No" selected="true">No</option>
        </select>
      </div>
      <div id="recurrence_pattern">
        somethings ..................
      </div>
    </fieldset>
  </form>
</div>

JavaScript

$(document).ready(function() {
  $("#id_recurring_event").change(function() {
    if ($(this).val() === "No") {
      $('#recurrence_pattern').hide();
    } else {
      $('#recurrence_pattern').show();
    }
  });
  $("#id_recurring_event").trigger("change")

})