<!DOCTYPE html>
<html>
<body>
<p>Press a key on the keyboard in the input field to find out if the ALT key was pressed or not.</p>
<input type="text" onkeydown="isKeyPressed(event)">
<p id="demo"></p>
<script>
function isKeyPressed(event) {
var x = document.getElementById("demo");
if (event.altKey) {
x.innerHTML = "The ALT key was pressed!";
} else {
x.innerHTML = "The ALT key was NOT pressed!";
}
}
</script>
</body>
</html>