Search notes:
JavaScript: NaN
<!DOCTYPE html>
<html>
<head>
<meta content="text/html;charset=utf-8" http-equiv="Content-Type">
<title>NaN</title>
<script type="text/javascript">
function main() {
var out = document.getElementById('out');
out.innerHTML += typeof(NaN) + "<br>"; // number
out.innerHTML += NaN + 5 + "<br>"; // NaN
out.innerHTML += NaN + Infinity + "<br>"; // NaN
out.innerHTML += NaN +'Foo' + "<br>"; // NaNFoo
}
</script>
</head>
<body onload='main()';>
<div id='out'>
</div>
</body>
</html>