JSFiddle - React, Tailwind, and code Playground

by geko

HTML

<div id="content-body" class="clearfix">

        <!-- detail div no 1 = 3 items inside -->
            <span class="countDiv0"></span> 
            <div class="detail">
                <div class="box">
                    Div item 1
                </div>
                <div class="box">
                    Div item 2
                </div>
                <div class="box">
                    Div item 3
                </div>
            </div>
            <br /><br />
            <!-- detail div no 1 = 4 items inside -->
            <span class="countDiv1"></span> 
            <div class="detail">
                <div class="box">
                    Div item 1
                </div>
                <div class="box">
                    Div item 2
                </div>
                <div class="box">
                    Div item 3
                </div>
                <div class="box">
                    Div item 4
                </div>
            </div>

        </div>

JavaScript

$('.detail').each(function(i) { 
            var n = $(this).children('.box').length;
            $(".countDiv"+i).text("There are " + n + " divs inside parent box detail.");
        });