<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("h1").add("p").add("span").css("background-color", "yellow");
});
</script>
</head>
<body>
<h1>Welcome</h1>
<p>A p element.</p>
<p>Another p element.</p>
<span>A span element.</span>
<span>A span element.</span><br><br>
<div>This example adds the same css style for both p and span elements, as the existing h1 element.</div>
</body>
</html>