JSFiddle - React, Tailwind, and code Playground

HTML

<div class='mydiv'>
    <p>blabalbalala</p>
    <p>blabalbalala</p>
    <p>blabalbalala</p>
    <p>blabalbalala</p>
</div>

CSS

.incluido{
    color: #ccf;
}

JavaScript

var els = Array.prototype.slice.call(document.querySelectorAll('.mydiv p'));

var incluidos = els.filter(function(el){
   return el.getBoundingClientRect().top < 30; 
});

incluidos.forEach(function(el){
   el.classList.add('incluido'); 
});