JavaScript Tutorial

.hasClass()

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
  $("button").click(function(){
    alert($("p").hasClass("intro"));
  });
});
</script>
<style>
.intro {
  font-size: 120%;
  color: red;
}
</style>
</head>
<body>
<h1>This is a heading</h1>
<p class="intro">This is a paragraph.</p>
<p>This is another paragraph.</p>
<button>Does any p element have an "intro" class?</button>
</body>
</html>