Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script>
$(document).ready(function(){
    $("button").click(function(){
        $("p, h1").removeClass("head intro main");
    });
});
</script>
<style>
.head {
    font-size: 2em;
    color: green;
}

.intro {
    font-size: 120%;
    color: red;
}

.main {
    font-size: 20px;
    color: blue;
}
</style>
</head>
<body>

<h1 class="head">This is a heading</h1>

<p class="intro">This is a paragraph.</p>
<p class="main">This is another paragraph.</p>

<button>Remove the "head", "intro" and "main" class from the selected elements</button>

</body>
</html>