JSFiddle - React, Tailwind, and code Playground

HTML

<select id="input.date_of_birth">
<option></option>
<option value="2000">2000</option>
<option value="1999">1999</option>
<option value="1998">1998</option>
</select>


<p>find('option') = <span id="result_1"></span> elements</p>
<p>parent().find('option') = <span id="result_2"></span> elements</p>

JavaScript

$(function(){
  var s = $("select[id='input.date_of_birth']");
  $('#result_1').text(s.find('option').length); // finds zero elements
  $('#result_2').text(s.parent().find('option').length); // finds 4 elements
});