JSFiddle - React, Tailwind, and code Playground

HTML

<select class="item-number">
  <option>Please select</option>
  <option value="123" label="Description about 123">123</option>
  <option value="456" label="Description about 456">456</option>
</select>
<span class="item-name">Description shows up here</span>

JavaScript

$('.item-number').change(function() {
  if $('.item-name').html == "123"
  then
  $('.item-name').html("Test");
});