<!DOCTYPE html>
<html>
<head>
<script src="/lib/jquery-1.12.2.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
$("<span><b>Hello world!</b></span>").replaceAll("p:last-child");
});
});
</script>
</head>
<body>
<button>Replace every p element that is the last child of its parent, with a bold span element</button><br><br>
<div style="border:1px solid">
<p>The first paragraph in div.</p>
<p>The last paragraph in the div.</p>
</div><br>
<div style="border:1px solid">
<p>The first paragraph in another div.</p>
<p>The last paragraph in another div.</p>
</div>
</body>
</html>