JSFiddle - React, Tailwind, and code Playground

by web tiki

HTML

<div class="wrapper">
  <div class="class-a">xxx</div>
  <div class="class-a">xxx</div>
  <div class="class-b">xxx</div>
  <div class="class-b">xxx</div>
  <div class="class-b">xxx</div>
  <div class="class-b">xxx</div>
  <div class="class-b">xxx</div>
  <div class="class-b">xxx</div>
  <div class="class-c">xxx</div>
  <div class="class-c">xxx</div>
  <div class="class-c">xxx</div>
</div>

CSS

.selected{
    background:gold;
}

JavaScript

var child_num = 0;
$('.wrapper > .class-b').each(function(){
    if(child_num < 3){
        $(this).addClass('selected');
    }
    child_num++;
});