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<div id="containsClassExample" class="highlight">
This element's classes will be checked.
</div>
<button onclick="checkClass()">Check Class</button>

<script>
function checkClass() {
const element = document.getElementById('containsClassExample');
if (element.classList.contains('highlight')) {
alert('The element has the highlight class.');
} else {
alert('The element does not have the highlight class.');
}
}
</script>

<style>
.highlight {
background-color: yellow;
}

.text-large {
font-size: 24px;
}
</style>