Alerta de função, confirmar, prompt

<!DOCTYPE html>
<html>
<body>

<button onclick="myFunction()">Try it</button>


<script>
function myFunction() {
    var name = prompt("Please enter your name", "XYZ");

    if (name != null) {
       alert('Your name is ' + name )


    }
}
</script>

</body>
</html>
Matthew Roxas