NovichokJS,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<script>
document.addEventListener("click", function({target : {classList, textContent}}) {
if(classList.contains("btn")) console.log(textContent);
})
</script>
</head>
<body>
<button class="btn">JavaScript</button>
<button class="btn">HTML</button>
</body>
</html>