<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
document.write(isNaN(parseInt("123")));
document.write("<br>");
document.write(isNaN(parseInt("A123")));
document.write("<br>");
document.write(isNaN(parseInt("123A")));
document.write("<br>");
document.write("<hr>");
document.write(isNaN(Number("123")));
document.write("<br>");
document.write(isNaN(Number("A123")));
document.write("<br>");
document.write(isNaN(Number("123A")));
document.write("<br>");
</script>
</head>
<body>
</body>
</html>