SO-34923221

by David Thomas

HTML

<div id="mydiv" class="a"></div>
<div id="myotherdiv"></div>

CSS

div {
  height: 2em;
  border: 3px solid limegreen;
  margin-top: 0.5em;
  border-radius: 1em 0;
}

.found {
  border-color: orange;
}

JavaScript

//
//
function hasClasses(node) {
  return node.classList.length > 0;
}

var elem1 = document.getElementById('mydiv'),
  elem2 = document.getElementById('mydiv');

if (hasClasses(elem1)) {
  elem1.classList.add('found');
}
if (hasClasses(elem2)) {
  elem2.classList.add('found');
}