<!DOCTYPE html>
<html>
<body>
<h1>My First JavaScript</h1>
<p>JavaScript can change the content of an HTML element:</p>
<button type="button" onclick="myFunction()">Click Me!</button>
<p id="demo">This is a demonstration.</p>
<script>
function myFunction() {
document.getElementById("demo").innerHTML = "Hello JavaScript!";
}
</script>
</body>
</html>