JSFiddle - React, Tailwind, and code Playground

HTML

<h1>
Start Time
</h1>
<select id="startTime">
  <option value="na">Pick a time</option>
  <option>12:00pm</option>
  <option>1:00pm</option>
  <option>2:00pm</option>
  <option>3:00pm</option>
  <option>4:00pm</option>
</select>
<hr>
<h1>
End Time
</h1>
<select id="endTime">
  <option value="na">Pick a time</option>
  <option>12:00pm</option>
  <option>1:00pm</option>
  <option>2:00pm</option>
  <option>3:00pm</option>
  <option>4:00pm</option>
</select>

JavaScript

$('#endTime').css('display', 'none');

$('#startTime').change(function () {
	if($('#startTime').val() !== 'na') {
    $('#endTime').css('display', 'initial');
  }
});