JSFiddle - React, Tailwind, and code Playground

HTML

<div id="1">
<span class="class1"></span>
<span class="class5"></span>
</div>

JavaScript

var something = 1;

$("#" + something).children(".class5").html(function() {
  var id = +$(this).closest('div').attr('id');
  $(this).html('Typeof id: ' + typeof id + id);
});