JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="item">item 1</div>
    <div class="item">item 2</div>
    <div class="item">item 3</div>
    <div class="item">item 4</div>
    <div class="item">item 5</div>
    <div class="item">item 6</div>
    <div class="item">item 7</div>
    <div class="item">item 8</div>
    <div class="item">item 9</div>
</div>

CSS

.container {
    border: 1px solid red;
    padding: 10px;
}

.item {
    display: inline-block;
    border: 1px solid green;
    width: 200px;
    margin: 10px;
}

JavaScript

var top;
$('.container .item').each(function(i){
    var thistop = $(this).offset().top;
    if (i==0){
        top = thistop;
    }
    if (top==thistop){
    	$(this).css({borderColor:"purple"});   
    }
});