JSFiddle - React, Tailwind, and code Playground

HTML

<div id="js-test" class="test"></div>

CSS

body {
  margin:0;
}
.test {
  background:#DDD;
  width:300px;
  height:100px;
  text-align:center;
  line-height:100px;
}
.test-red {
  background:red;
}

JavaScript

let test = document.getElementById('js-test');
test.innerHTML = test.clientWidth + ' - ' + document.documentElement.clientWidth;

window.addEventListener("resize", function(){
  test.innerHTML = test.clientWidth + ' - ' + document.documentElement.clientWidth;
  
  if (test.clientWidth > document.documentElement.clientWidth) {
  	test.classList.add('test-red');
  } else {
  	test.classList.remove('test-red');
  }
});