<html>
<title>W3.JS</title>
<script src="w3.js"></script>
<body>
<p><button onclick="w3.toggleShow('#London')">Click to Toggle Hide/Show</button></p>
<div id="London">
<h2>London</h2>
<p>London is the capital city of England.</p>
</div>
</body>
</html>