<html>
<body>
<script>
var txt="Hello World!";
document.write("<p>" + txt.toUpperCase() + "</p>");
document.write("<p>" + txt.toLowerCase() + "</p>");
document.write("<p>" + txt + "</p>");
</script>
<p>
The methods returns a new string.
The original string is not changed.
</p>
</body>
</html>