JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<div id="fatherDiv">
  <div id="childDiv1">
    <h4>Div 1</h4>
  </div>
  <div id="childDiv2">
    <h4>Div 2</h4>
  </div>
  <div id="childDiv3">
    <h4>Div 3</h4>
  </div>
  <div id="childDiv4">
    <h4>Div 4</h4>
  </div>
  <div id="childDiv5">
    <h4>Div 5</h4>
  </div>
  <div id="childDiv6">
    <h4>Div 6</h4>
  </div>
  <div id="childDiv7">
    <h4>Div 7</h4>
  </div>
</div>

JavaScript

$('#fatherDiv > div').each(function() {
  if ($(this).css("background-color") !== 'red') {
    $(this).css("background-color", "red");
  }
});