<script>
function myFunction(valNum) {

    var age;
        if (x < 14) {
            age = "child.";
            break;
        } else if (x > 13 && x < 19) {
            age = "teenager.";
            break;
        } else if (x > 19) {
            age = "adult.";
        }
document.getElementById("demo").innerHTML="You're a" + age;

}
</script>