Untitled

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
    $("button").click(function(){
        $(".test").hide();
    });
});
</script>
</head>
<body>

<h2 class="test">Nagłówek o klasie test</h2>

<p class="test">Paragraf o klasie test.</p>
<p>Inny paragraf.</p>

<button>Kliknij!</button>

</body>
</html>