JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div_one" class="btn active"></div>
<div id="div_two" class="btn"></div>
<div id="div_three" class="btn"></div>
<div id="qwe_four"  class="btn"></div>

JavaScript

function check () {
	var elements = document.querySelectorAll('[id^="div_"]');
	var divId = elements.forEach(function(item) {
		if (item.className == "btn active") {
			return item.id;
		}
	});
  return divId;
}
var testVar = check();
alert(testVar);