Validating data with JavaScript

<!DOCTYPE html>
<html>
<body>

<p>Guess my age:</p>

<input id="age" type="number">

<button type="button" onclick="myFunction()">Enter</button>

<p id="abc"></p>

<script>
function myFunction() {
    var x, text;

    x = document.getElementById("age").value;

    if (isNaN(x) || x < 19) {
        text = "Too young!";
    }
    else if (isNaN(x) || x > 19) {
             text = "Too old!";
    }
    else {
        text = "Correct!";
    }
    document.getElementById("abc").innerHTML = text;
}
</script>

</body>
</html>