JSFiddle - React, Tailwind, and code Playground

HTML

<div class="column" id="column0">
	<div class="block0" id="block3">test</div>
	<div class="block0" id="block2">test</div>
	<div class="block4" id="block1">test</div>
	<div class="block2" id="block0">test</div>
</div>
<div class="column" id="column1">
	<div class="block0" id="block13">test</div>
	<div class="block0" id="block12">test</div>
	<div class="block4" id="block11">test</div>
	<div class="block2" id="block10">test</div>
</div>
<div class="column" id="column2">
	<div class="block0" id="block23">test</div>
	<div class="block0" id="block22">test</div>
	<div class="block4" id="block21">test</div>
	<div class="block2" id="block20">test</div>
</div>

CSS

.column{
	float: left;
    padding: 10px;
}

JavaScript

var getBlockInColumn = function() {
	thisColID = $(this).attr('id');
	alert($("div#" + thisColID + ":first-child").attr('id'));
};

$(document).ready(function(){
	$(".column").on("click",getBlockInColumn);
});