<!DOCTYPE html>
<html>
<body>
<p>Click the button to display a time-based greeting:</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var hour = new Date().getHours();
var greeting;
if (hour < 18) {
greeting = "Good day";
} else {
greeting = "Good evening";
}
document.getElementById("demo").innerHTML = greeting;
}
</script>
</body>
</html>