JSFiddle - React, Tailwind, and code Playground

HTML

<div id="SomeID">
 <div class="Wrapper">
    <input type="checkbox" class="SomeCheckboxClass">
    <input type="checkbox" class="SomeCheckboxClass">
    <input type="checkbox" class="SomeCheckboxClass">
 </div>

 <div class="Wrapper">
    <input type="checkbox" class="SomeCheckboxClass">
    <input type="checkbox" class="SomeCheckboxClass">
    <input type="checkbox" class="SomeCheckboxClass">
 </div>
</div>

JavaScript

$('.Allcheckbox').on('click', function() {
    var nb = $('input:checked').length;
   
});
 console.log(nb);